DE3108242A1 - Method for the calorific measurement of the power loss of a gear and a device for carrying out the method - Google Patents

Abstract

During the calorific measurement of the power loss of a gear, the gear is heat-insulated and the heat resulting from the power loss is preferably conducted away with the gearing oil with the aid of a heat sink, in particular of a heat exchanger (11). When the operating state of the gear (1) changes, the power loss which occurs and thus the amount of heat to be conveyed away also changes. The various measuring points can be quickly determined without long waiting times if, according to the invention, the temperature of the gear (1) is kept constant independently of the respective operating state. This is achieved preferably by determining the gear temperature, in particular by measuring the temperature in the oil sump by means of a heat sensor (32) which, in the event of a change in the operating state and in the associated tendency of the gear temperature to rise or fall, issues via a temperature controller (31) an appropriate instruction to a speed of revolution actuator (30) which itself acts on a drive motor (13) of the feed pump (12) in the circuit (1,7,11,8). The heat loss is determined via the amount of coolant flowing through the secondary side, with the aid of the flow meter (23) and of a temperature differential meter (34). In order to avoid heat being conducted away via the connection shafts (2 and 3) which are guided through towards the outside, these are preferably placed at the same temperature, which also constitutes the set value for the controller (31), with the aid of devices (38 and 39). <IMAGE>

Description

Research Institute for Motor Vehicles and FshrzeugjTictoren Stuttgart - F.KFS Pfaffenwaldring 12th

7000 Stuttgart 80

Method for calorie measurement of the power dissipation of a Transmission and

i £ ht \ m g to O urclr Guide e g · · Verfat of the proceedings. Ί

The invention relates to a method for caloric measurement of the power loss of a transmission, in which at constant mechanical failure of the transmission of this load Corresponding heat content of the measuring system through "arm insulation at least the rfetriebHS and a heat sink in one Circuit of the Strönunf medium dissipating the power loss kept constant and the amount to be discharged from the "weight sink"

BAD ORlGJNAL

- 7 heat output is determined. The further relates to Invention to a device according to the preamble of the claim 6th

Part of the mechanical enforced by a gear Power is due to the inevitable? Eibu: ig in heat output implemented. This heat output is dissipated by conduction, radiation or convection, so that in a certain Operating state sets a heat equilibrium, i.e. this gearbox assumes a certain operating temperature. In case of need, especially with larger heat outputs, can an increased cooling with HiITe a flowing through the gear, preferably liquid medium connected to a heat sink.

In itself, one could calculate the power loss of a gear unit from the difference between the ireeharian power to be conducted and the output determined by calculation, but this method is relatively imprecise because the power loss in many operating states is small compared to the enforced mechanical performance. As a result, one draws for a more accurate measurement the heat output resulting from the friction. this leads to a much more accurate process. Theoretically, exact values are obtained if the gearbox is completely isolated, the power loss constant and also a constant temperature field available. Because with insulation, the heat

COPY

discharged from the gear unit by means of an especially liquid flow medium and discharged to a heat sink ^; ·

must, at least the latter must also be isolated, preferably but the whole system. The amount of heat dissipated via the heat sink can be recorded exactly. So if 'according to the preceding The prerequisites are constant heat content is, it follows from the energy balance; that the in the Heat sink dissipated amount of heat is equal to the power loss of the transmission to be checked.

The known method works according to the method described above. If you disregard the fact that it is perfect insulation difficult to achieve and the detection of losses is not easy, the previously known method is one In itself a relatively precise method for recording the power loss of a gearbox.

The power loss of a transmission depends on its operating state addicted. As a result, they have to be applied to different ones Determine operating conditions in order to be able to set up tables and / or diarrams with the help of individual measuring points. Because the power loss, As I said, a different one for each operating state the transmission becomes colder or warmer when the operating status changes. Only then can a measurement be taken be carried out 'when a constant temperature distribution and there is a constant heat content of the system. This can

BAD ORIGINAL _{QQpy {}

3 + 08242

take a relatively long time, for example over an hour. It is obvious that the acquisition of characteristic diagrams of the gearbox with many measuring points can take days and this method is at least for a series control uneconomical if gpr is not unusable. To the Checking vehicle transmissions, this method is not only unsuitable for the reasons mentioned, but also from other reasons, above all in the problem of insulation and the achievement of a constant heat content of the system lie.

The object of the invention is therefore the method of the type mentioned so that the measurements during the transition from one operating state to one

! others in a much shorter time with at least the same accuracy can be carried out, and a device .; to the Carry out this procedure to create.

To solve this problem, it is proposed according to the invention that that the method according to the preamble of claim 1 is designed according to the characterizing part of this claim. Because, now the heat content of the measuring system, which is essentially from the gearbox as well as the heat sink and connecting lines and a conveying device for the flow medium is constant, regardless of the load on the gearbox is held, one can in the desired wines the one

Determine the power loss that can be assigned to specific gear loads relatively quickly during the transition from one load value to another. In contrast to the previously known method, in which the gearbox and all its parts have to heat up or cool down from one load level to another in the manner corresponding to this 3 load level, which takes up the time span mentioned, becomes beer the heat content of the gear unit u ^ d in addition also d <= o of the entire measuring system kept constant by reduced or increased dissipation of heat , depending on whether the load is lower or higher than the previous one. These: - Adjustment of the new ^T - ^R ertes for the * 'ir me dissipation la of the heat sink, which can be, for example, a heat exchanger , much faster than the heating or cooling of the whole process, as required by the previously known method With the inventive method, a new, constant heat content is achieved after just a few minutes.

A further development of the invention provides that the ρ Is systematic measurement error occurring ^τ '· ^τξ ίπ "β loss of the ^T -ie? system at different transmission loads is determined and added to the heat dissipated by the heat sink. This heat loss is Naturally, the lower, the better the insulation is carried out. That is why it is also important that the entire circuit of the power dissipating Strc- "iun, q; sraediu," ß viärineisoliert vlrd ^ sIe! dunking the gearbox from and

BAD ORiGINAL

J1.10 82 k 2

to dispense with the heat sink and the temperature of the flow medium directly at the exit from the gearbox and at the entrance measure into the gearbox, but this is not useful if the accuracy requirements are high if the flow medium is oil Is oil, which is used in a preferred manner, in the primary circuit of a heat exchanger? the advantage because it can also be used as a lubricant for the gearbox. On the other hand, however, oil tends to be included of air in the form of bubbles, and the latter can falsify the measurement result. On the secondary side, one does not speak with one Heat exchanger preferably water, in which this problem occurs less.

However, because the thermal insulation cannot be carried out one hundred percent with reasonable effort, and also a certain amount Loss via the gear shafts passed through the insulation to the outside cannot be avoided without taking special measures is, the measuring system is calibrated by supplying it with a certain amount of heat per unit of time in an advantageous manner and checks how much of it is dissipated with the aid of the heat sink must be when the temperature in the measuring system is constant is held. The difference between the amount of heat supplied and the amount of heat removed by the heat sink is that of the Heat transmission caused heat loss. According to the different Operating states of the transmission can also be caused by undesired heat radiation and heat conduction

BAD ORJGiSSiAL °° ^ΡΥ

Record heat loss by varying the amount of heat supplied. Here ,, as well as in the preceding and following explanations, it is assumed that the transmission is in the idle state has a certain temperature and this is due to it the power loss increases, regardless of whether the

; Temperature of the transmission in the idle state a positive or negative degree Celsius value.

A further development of the process is characterized ! by that at least part of the thermal insulation of the

: Transmission elements and / or transmission

; Fortifications or the like, preferably outside the thermal insulation heated or cooled, especially to the Ternperatur-

: level of the transmission is brought. The thermal insulation is in

Normal case interspersed with a drive shaft for the gearbox and an output shaft. In addition, each can have a gearbox ^; be also added a shift linkage. The losses in the latter are negligible, so that special measures in normal cases are unnecessary at this point. On the other hand, the heat loss via the gear shafts mentioned is not negligible. In many cases that are of interest in practice, the gear temperature of the loaded gear is different from the temperature of a drive motor or other devices connected to the gear shafts, for example, so that there is a heat gradient from the inside to the outside or vice versa with respect to the gear, i.e. heat is dissipated via the gear shafts. or to-

flows. If you now run these outer "drive shaft parts" through |

^C0PY BAD ORIGINAL

3Ί08242 -r: ":: VV";. χ 1

- 13 brings heating or cooling to a preset value and If this value is maintained during the test, it is easily possible on the basis of the known value of the temperature inside the gear unit to determine the heat flow through these waves arithmetically and in the overall result of the measurement of the power loss consider. It is then of particular advantage that, according to the method according to the invention, c'ie temperature of the Transmission and thus also inside the transmission is kept constant.

The above-mentioned development of the method is however In addition, the possibility of the external shaft parts to bring to the same temperature that is kept due to the control inside the gearbox. As a result, everyone stays away Heat flow to the outside, which, especially in connection with good insulation, causes the systematic measurement error to be extraordinary is decreased.

There is another embodiment of the method according to the invention in that in an operating state in which the mechanical power loss of the transmission is less than the heat insulation loss, the flow medium is supplied with a heat output dimensioned such that the heat content of the measuring system increases the value is maintained that corresponds to this operating state, and that the supplied heat output to that at the heat sink dissipated heat output is added. In this case, the whole system for carrying out the method includes except for the Heat sink a source of heat. This can also be added to the

. - 14 -

already mentioned calibration can be used, with which one the Determined heat loss of the feet system. The operating state of the transmission to be checked can be defined by the speeds and torques on the input and output shafts as well by the gearbox temperature.

According to the invention, the object is also achieved still proposed that a device according to the preamble of claim 6 according to the characterizing part of this claim is trained. "If, based on a certain operating or load condition of the transmission, this operating condition is changed, so this has an increase or decrease in the friction and thus also the resulting heat output this friction loss result. If one assumes that the friction and thus also the heat output in the new operating state is lower than the previous one, this would lead to a reduction in the transmission temperature for the same heat sink performance to lead. Due to the temperature controller's sensor, which is preferably located in the gearbox, the Sensitivity of the temperature controller determines the corresponding temperature drop and the controller then effects it a reduction in the amount in circulation of the power loss purging disturbances and / or a reduction in Flow velocity. The adjusting device is expedient the pump a speed setting device, which reduces the speed of the feed pump for the flow medium or if necessary also increased. The heat output of the heat sink therefore forms the manipulated variable in the control loop. ~ r

COPY

In the case of a "device whose cooling device ⁴ "'.g is designed as a heat exchanger, the primary side of which is in the circuit of the flow medium dissipating the power loss and a cooling medium, in particular water, flows through its secondary side, a further development of the invention consists in that the cooling medium flows through the secondary side due to the level difference of a regulated level on the inflow and outflow side and there is an adjustable throttle device in the inflow line

, - .. regulate the output of the heat sink. In addition, the upstream side increases also put on a volume meter.

A preferred embodiment of the invention provides that in an Eypass to the part of the leading through the transmission

ι circuit for the dissipation of the power dissipation flow-I

dium a particularly controllable heat source, preferably one electric heater, is built in. This can lead to the aforementioned Purposes, in particular to determine

the detectable systematic measurement error of the measurement system. Before-- In some cases, a second, preferably one, is located in the bypass of the circuit of the flow medium dissipating the power loss adjustable pump with which the flow rate can be changed by the heat source.

A preferred variant of the invention provides that at least the part of the gear shafts that is outside the thermal insulation with

3TO 8242

a device for heating and / or cooling is provided. This device is used in accordance with the foregoing in particular, the level of the external gear shaft part to bring to that of the isolated gear.

Another embodiment of the invention is that the Device for heating and / or cooling the gear shafts or the like in the manner of at least a part of the external one Transmission shaft part uir giving cuff or the like. Is formed, which has a connection for an admission of a heat transfer medium and a drain for the latter has. If you are a bearer Air used., So one saves the recirculation. In this case it is sufficient if the cuff has a connecting piece has a simple opening in the for the air at a given temperature, while allowing the air to flow out Cuff is sufficient.

A further development of the invention provides that the heat transfer medium a preferably controllable heat source, in particular an electrical one, for changing the temperature of the transmission shaft ends and the like Heating, flows through, whereby the heat sensor for the bowler inside the cuff. The sucked in air is forced through a heating device by means of a fan, the performance of which can be changed by the controller as a function of the air temperature in the cuff determined by the sensor .

In the drawing is an embodiment of the invention Device shown is show:

Figure 1 is a block diagram of the device for performing the method,

FIG. 2 shows a section through a transmission to be tested with part of the device to carry out the procedure,

FIG. 3 shows, on an enlarged scale, a detail from FIG. 2 with another part of FIG Device for carrying out the process,

a section of the gearbox housing in a further enlarged view and a bracket for the gearbox.

The transmission 1, which, for example, zxvei connecting shafts and 3, of which one forms a drive shaft and the other forms an output shaft, is surrounded by insulation 4. In this insulation there is also a symbolically drawn Se halt s tan ge 5 embedded. It is a gear with oil lubrication, its in the form of a filsump in the gear housing

• · * J

- 18 -

6 located oil can flow off via a line 7 and flow back again via a line 8. This oil flow is symbolized by arrows 9 and 10. From the line 7 the oil first reaches the heat exchanger 11 and from there via the line 8 back into the transmission housing 6. The oil is transported with the aid of a pump 1? made, which is driven by a controllable Kotor 13 vird. With dot-dash lines 14 in Fig. 1 symbolizes j that the lines 7 and 8 as well as the pump 12 and the heat exchanger. ¹ I are surrounded by an insulating layer 15.

The primary side of the heat exchanger 11 is denoted by 16 and the secondary side by 17. The heat exchanger 11 is a heat sink, that with it, the up in the gear ^housing: due to the power loss of heated oil-cooled. To this end ! cooling water is fed to the secondary side 17 of the heat exchanger 11 via a line 18 and leaves the heat exchanger via the line 19. This cooling water is taken from a container 20 and pelarged into a second container 21 - Peide ^ containers have a regulated level, so that a constant height of fall 22 results. In the supply line 1? there is a flow meter 23 and an adjustable throttle 2.4.

A bypass line 25 is also used, in particular for calibration purposes provided, in which a second pump 26 and a heat source 27j, for example, an electric heater.

_ IO _

A motor 28 is used to drive the second pump 26 it is expediently an AC motor., while the Ho tor 13 is a controllable DC motor. Consequently a rectifier 29 is also provided, the direct current side of which is also connected to a speed controller 30 is. This receives its commands from a temperature controller 31, whose sensor 32 is inside the gearbox, for example in the oil sump, is located.

The secondary medium-α of the heat exchanger 11, that is to say d? A Water is not only used in terms of its flow rate, but also with regard to its inlet and outlet temperature

door captured. For this reason, i

a first heat sensor 33 and a second heat sensor 34 installed in the drain line 19. Temperatures will however not determined individually, rather the difference temperature is determined with the help of the temperature difference meter ■ 49. Accordingly, the power loss of the transmission results from the displays of the temperature difference meter 49 and the Kengenmeter 23

The transmission is attached to a bracket 35, for example, whereby to avoid heat loss between the last tere and the gear housing or the insulation 4 is a heat insulating Layer 36 is connected, which prevents metallic contact.

31-Θ-824-2

j Because in normal cases with a loaded gear unit the temperature in the Ί
[Gear inside unc ¹ . dan.it also the temperature of the connecting shafts 2 and 3 is higher than the outside temperature or the temperature; a drive motor, not shown, for this transmission are; the outer ends of the connection shafts 2 and 3 and possibly also connecting flanges r: with a continuing line 37 of a respective heating device 38 or vr. 39 surrounded. Basically, these are simple collars which give the relevant shaft parts, couplings and the like in a contact-free manner and which, if necessary, can also be designed in the manner of a labyrinth seal. In order to avoid recirculation of the heat transfer medium for heating these shaft parts, air is preferably used as the heat transfer medium. ^This: is fed via a line 40 and leaves the device in the axial direction in the sense of arrows 41. ¹ ^ s is readily apparent that one of the? We5.se can also cool the waves in case of need, if you supply cooled air instead of heated air. In addition, the device 38 or 39 is not limited to the medium air or gas, although for the sake of simplicity only air will be referred to below.

The parts required for heating the outer shaft parts Air is sucked in with the help of a fan 42, which is from a Motor 43 is driven. It first goes through a heating device 44, where they are brought to the desired temperature

COPY

- turns 21. The power of the heating coil 4.5 or crl. is regulated with the help of a power controller 1-6 , which is controlled by a level 47. The latter has a temperature sensor 48 which is mounted inside the heating device 38 or 39.

To determine the power loss of the transmission 1, at least one of its connecting shafts 2 and 3 is driven and braked if necessary. A very specific, precisely determined operating state is regulated. Due to the power loss in the gearbox and its insulation, the gearbox and thus also the gear oil heats up. With the aid of the punoe 12, this oil is drawn off and pumped through the primary side 16 of the heat exchanger 11. Part of the secondary side 17 of which colder water flows through, the oil cools down in the heat exchanger 11 and flows back into the transmission via the line 8 at a reduced temperature. If the various relevant parameters are not changed, an equilibrium of heat is established after a while. If one disregards certain heat losses, which will be discussed below, the power loss of the transmission in this operating state can be determined in the manner described after this thermal equilibrium state has been reached.

If the operating state is changed, this leads to a greater or lesser power loss. Would you consider the performance of the

Heat sink, ie the heat exchanger 11, maintained, this would lead to heating or cooling of the transmission, depending according to whether the Felastunc- increases or decreases. because However, according to the invention, the temperature of the gear unit is constant is held, the performance of the heat exchanger 11 must be changed will. As a result, one has to be on the primary and / or secondary side increase the throughput of the primary and / or secondary media. This is achieved on the primary side by changing the pump output on the pump 12 and on the secondary side by a other setting of the throttle device 24. The change the pupil power takes place automatically but the temperature sensor 32, the temperature controller 31 and i-an speed controller 30 for the pump motor 13. Secondary side: one can see a comparable one Provide control for the adjustable throttle device 24. In one embodiment, however, we only have the Friraärseite regulated.

For calibration purposes, but possibly also to carry out the method according to the invention with low power losses in relation to the insulation losses of the measuring system, a controlled amount of heat can additionally be supplied to the medium of the primary circuit with the aid of the heat source 27. For calibration, the idling power of the gearbox is averaged mechanically. ^{This mechanical power and the heat power supplied via} the heat source 27 is controlled by the cooling power of the heat exchanger. The difference is the loss of insulation when the temperature of the "eating" is kept constant.

COPY BAD ORIGINAL

34082-42

^T iit means of the devices 3 ^ · and 39, the parts of the connecting shafts 2 and 3 and optionally also Weni be ^ - least a portion of the secondary skins ar:. F a predetermined temperature brought, wherein zweckmäM ^ legally un the temperature is. , which is kept constant with the help of the sensor 32 in the drive. In the latter .Falle avoiding an ^m emperatur.cefalle to this Anschlußxvellen from outside to inside and vice versa, and thus can then be ¥ -> l.rneab flow en prevent iebeinnern us the Get ^?. On the other hand, however, the energy required to heat the outer cell parts can be precisely determined, if one needs to know this from beyond anything.

¹ ^ aS erfindungs'-eraäße method is suitable not only ira Susanne Hans; with a mechanical transmission, but also for measuring other types of transmission, such as a hydraulic converter. Corresponding ritual for the device for carrying out the method.

BAD ORJGiNAL

Claims (13)

Patent attorney DIPL.-WGoBER-THGLD'-SCEfMID STUTTGART 1 FALBENHENNENSTRASSE 17 TELEPHONE (0711) 608893 UNSEB SIGN lh 089 Expectations Iy method for caloric measurement of the power loss of an Oetrlebe (1), in which, with constant mechanical load on the transmission, the heat content of the measurement system (1, 7, 16, B) corresponding to this load by thermal insulation (4, 15) of at least the transmission and a heat sink (11) in a circuit (1, 7, 11, 8) of the Strörnunesmediuras, which dissipates the power loss, is kept constant and the heat output to be dissipated by the heat sink is determined, characterized in that the heat content of the measuring system (1, I ₁ 16, 8) is kept constant regardless of the load on the gear unit (1). 2. The method according to claim 1, characterized in that the occurring as a systematic measurement error heat loss of the WebSystems (1, 7, 16, 8) for different transmission loads determined and to the heat output dissipated by the heat sink (11), is added. - 2 3 · Method according to claim 1 or 2, characterized in that the entire circuit (1, 7, 11, 8) of the power loss discharging flow medium is thermally insulated. 4. The method according to at least one of the preceding claims, characterized in that at least part of the the heat insulation (4) of the gear (1) penetrating gear elements (2, 3, 5) and / or gear mountings (35) Od. The like. Preferably heated or cooled outside the thermal insulation (4), in particular to the temperature level of the Transmission (1) is brought. 5. The method according to at least one of the preceding claims, characterized in that in an operating state in which the mechanical power loss of the transmission is smaller is the same as the heat insulation loss, the flow medium Measured heat output is supplied that the heat content of the ileßsystems is kept at the value that this operating state corresponds, and that the supplied heat output is added to the heat output dissipated at the heat sink. 6. Device for performing the method according to at least any one of claims 1 to 6; with a gear (1) and a cooling device (U) for the flowing through the gear Flow medium, both of which are covered by a thermal insulation layer (4, 15) are surrounded, the cooling device (11) having a measuring device (23, 49) to record the amount of heat dissipated is permitted and the transmission and the cooling device and - 3 - a feed pump (12) are in a circuit (:, 7., 11. B), characterized in that the feed pump (12) is designed as a controllable pump., The adjusting device (30) of the Pump is connected to a temperature controller (31), the sensor (32) of which is in the circuit of the flow medium, in particular inside the gearbox. 7 · Device according to claim 6, characterized in that the adjusting device (30) of the pump (12) is a speed adjusting device is. 8. The device according to claim β or 7 ₃ whose cooling device is designed as a heat exchanger (11), its primary side (16) in the circuit (1, 7, 11, 8) of the flow medium dissipating the power loss and its secondary side (17) is traversed by a cooling medium, in particular water, characterized in that the cooling medium flows through the secondary side (17) on the inflow (18) and outflow side (19) based on the level difference (22) of a regulated level (20, 21) each on the inflow (18) and outflow side (19) unu an adjustable throttle device (24) is located in the inflow line (18). 9 device according to at least one of claims 6 to 8, characterized in that in a bypass (25) to the part of the circuit (1, 7, 11, R) leading through the transmission (1) for the flow medium dissipating the power loss one COPY in particular controllable heat source (27) - preferably one electric heating is used. 10. Apparatus according to claim 9, characterized in that in the bypass (2 ^) of the dissipating power dissipation. Flow medium is a second ₅ preferably controllable pump (26). 11. Device according to at least one of claims ⁽ to 10> characterized in that at least the part of the gear shafts (2, 3) lying outside the thermal insulation (4) is provided with a device for heating (38, 39) and / or cooling is. 12. The device according to claim 11, characterized in that the device (° R, 39) for heating and / or cooling the gear shafts (2, 1) and the like in the manner of a sleeve surrounding at least a part of the outwardly turning gear shaft part or the like. "Is that a connection (40) for an inlet of a heat transfer medium and an outlet (41) for has the latter. 13. The device according to claim 12 ,. characterized in that the heat transfer medium changes the temperature of the gear shafts and the like, a preferably controllable heat source, in particular electrical Heizunp (45) flows through, wherein the copy The heat sensor (48) for the controller (47) is located in the interior of the cuff ₅ 39).