Gearbox for a motor vehicle

Abstract

A gearbox for a motor vehicle. The gearbox comprises at least one fluid supply system. The fluid supply system comprises at least one pump. The fluid supply system comprises at least one fluid sump. The fluid supply system comprises at least one fluid reservoir. The fluid reservoir comprises at least a first fluid outflow leading into the fluid sump. The first fluid outflow can be controlled as a function of a state variable.

Claims

1. A gearbox for a motor vehicle, wherein the gearbox comprises at least one fluid supply system, wherein the fluid supply system comprises at least one pump, wherein the fluid supply system comprises at least one fluid sump, wherein the fluid supply system comprises at least one fluid reservoir, wherein the fluid reservoir comprises at least a first fluid outflow leading into the fluid sump, wherein the first fluid outflow can be controlled as a function of a state variable, wherein the fluid supply system comprises at least a second fluid outflow, wherein the second fluid outflow cannot be regulated.

2. The gearbox according to claim 1, wherein the gearbox comprises at least one clutch.

3. The gearbox according to claim 1, wherein the state variable is a fluid supply variable, wherein the fluid supply variable comprises at least one variable selected from: a fluid pressure; a fluid volume flow; a rotational speed of the pump; a rotational speed of a pump motor; a rotational direction of the pump; a rotational direction of the pump motor; a fluid requirement and a banking-up pressure.

4. The gearbox according to claim 1, wherein the first fluid outflow is controllable at least one of actively and passively.

5. The gearbox according to claim 1, wherein the first fluid outflow comprises one or more orifices or one or more restrictors.

6. The gearbox according to claim 1, wherein the first fluid outflow comprises at least one valve.

7. The gearbox according to claim 6, wherein the valve includes a temperature-dependent valve.

8. The gearbox according to claim 6, wherein the valve includes a pressure-dependent valve.

9. The gearbox according to claim 6, wherein the valve includes a temperature-dependent and pressure-dependent valve.

10. The gearbox according to claim 1, wherein the gearbox comprises at least one sensing device for sensing the state variable.

11. The gearbox according to claim 10, wherein the sensing device includes a pressure sensor.

12. The gearbox according to claim 10, wherein the sensing device includes a rotational speed sensor.

13. The gearbox according to claim 10, wherein the sensing device includes rotational direction sensor.

14. The gearbox according to claim 1, wherein the fluid reservoir can be filled by means of at least one of sprayed fluid and fluid diverted by at least one orifice.

15. The gearbox according to claim 1, wherein the fluid supply system comprises at least one filter.

16. The gearbox according to claim 1, wherein the gearbox comprises at least one gearbox housing, wherein the fluid reservoir is at least partially integrated into the gearbox housing.

17. The gearbox according to claim 1, wherein the gearbox comprises at least one actuator.

18. The gearbox according to claim 17, wherein the actuator comprises at least one control output, wherein the gearbox is configured in such a way that the control output simultaneously controls the pump and the first fluid outflow.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are illustrated by way of example in the figures and are explained in more detail in the description of the figures. In the drawings:

(2) FIG. 1 shows a schematic illustration of a first exemplary embodiment of a gearbox according to the invention;

(3) FIG. 2 shows a schematic partial illustration of a second exemplary embodiment of a gearbox according to the invention;

(4) FIG. 3 shows a schematic partial illustration of a third exemplary embodiment of a gearbox according to the invention;

(5) FIG. 4 shows a schematic partial illustration of a fourth exemplary embodiment of a gearbox according to the invention;

(6) FIG. 5 shows a schematic partial illustration of a fifth exemplary embodiment of a gearbox according to the invention;

(7) FIG. 6 shows a fluid viscosity profile with respect to a temperature model;

(8) FIG. 7 shows a schematic illustration of an internal gear wheel pump with a reversal ring in a first rotational position; and

(9) FIG. 8 shows a schematic illustration of an internal gear wheel pump with a reversal ring in a second rotational position.

DESCRIPTION OF PREFERRED EMBODIMENTS

(10) FIG. 1 illustrates a first exemplary embodiment of a gearbox 110 according to the invention.

(11) The gearbox 110 comprises at least one fluid supply system 112. The fluid supply system 112 comprises at least one pump 114.

(12) The fluid supply system 112 comprises at least one fluid sump 116. The fluid supply system 112 comprises at least one fluid reservoir 118. The fluid reservoir 118 comprises at least a first fluid outflow 120 leading into the fluid sump 116. The first fluid outflow 120 can be controlled as a function of a state variable.

(13) The fluid sump 116 can be, for example, a gearbox oil sump.

(14) The fluid reservoir 118 can in particular be configured to store at least a portion of a volume of fluid 174 in the fluid reservoir 118. The fluid sump 116 can be configured to store and/or contain at least a further portion of the volume of fluid 174.

(15) The fluid reservoir 118 can be, for example, at least one container.

(16) The gearbox 110 can comprise at least one clutch 122. The gearbox 110 can preferably comprise at least two clutches 122. The pump 114 can be, for example, a clutch cooling pump (CCP), in particular a pump 114 for cooling at least one clutch 122.

(17) Alternatively or additionally, the pump 114 can also be a pump 114 for actuating the clutch 122. The gearbox 110 can particularly preferably comprise a pump 114 for cooling a clutch, and additionally preferably two pumps 114 for actuating in each case one of two clutches 122.

(18) The state variable can be a fluid supply variable. The fluid supply variable can comprise at least one variable selected from a fluid pressure, a fluid volume flow, a rotational speed of the pump 114, a rotational speed of the pump motor 124, a rotational direction of the pump 114, a rotational direction of the pump motor 124, a fluid requirement and a ram pressure. The first fluid outflow 120 can be controllable actively and/or passively.

(19) For example, the first fluid outflow 120 can be controlled actively, in particular by means of a solenoid valve. Alternatively or additionally, the first fluid outflow 120 can be controlled passively, in particular by means of a pressure in a cooling fluid duct.

(20) The first fluid outflow 120 can comprise at least one orifice 130 and/or at least one restrictor and/or at least one valve 126, in particular at least one temperature-dependent valve and/or at least one pressure-dependent valve and/or at least one temperature-dependent and pressure-dependent valve.

(21) The orifice 130 can in the simplest case be merely at least one opening, for example at least one pipe orifice and/or at least one hole orifice, with a hydraulic diameter. The orifice 130 can be configured in such a way that fluid 174 can be discharged and/or runs off into the fluid sump 116 within a time interval. The opening, in particular a size of a cross-sectional face of the opening, can be configured, for example, in a controllable fashion.

(22) A criterion for actuating the opening can be, for example, a requirement of cooling oil in the fluid sump 116 and/or a fluid level in the gearbox 110.

(23) Fluid 174 can be discharged, for example in a controlled fashion into the fluid sump 116, preferably as a function of a cooling fluid pressure of a clutch cooling means.

(24) The fluid supply system 112 can comprise at least one second fluid outflow 128. The second fluid outflow 128 can preferably not be capable of being closed-loop controlled. The second fluid outflow 128 can comprise at least one orifice 130. In particular, the second fluid outflow 128 can be an orifice-controlled outflow, for example in order to make available all the fluid 174 in the fluid sump 116 for the purpose of starting in the case of long immobilization times.

(25) The gearbox 110 can comprise at least one sensing device 132 for sensing the state variable, in particular at least one pressure sensor 134 and/or at least one rotational speed sensor 136 and/or at least one rotational direction sensor 138.

(26) The sensing device 132 can, for example, be configured to measure, for example in the case of an active actuator, a pressure of the cooling fluid and/or to sense said pressure directly or indirectly. This pressure of the cooling fluid can be used, for example, for closed-loop control of the first fluid outflow 120.

(27) The fluid reservoir 118 can be filled by sprayed fluid 140 and/or by fluid 174 which is diverted by at least one orifice. The fluid supply system 112 can comprise at least one filter 142. The gearbox 110 can comprise at least one gearbox housing 114. The fluid reservoir 118 can be integrated at least partially into the gearbox housing 144.

(28) Alternatively to this, the fluid reservoir 118 can be arranged at least partially outside the gearbox housing 144.

(29) For example, the fluid reservoir 118 can be arranged inside the gearbox housing 144. Alternatively to this, the fluid reservoir 118 can be arranged outside the gearbox housing 144.

(30) For example, the fluid reservoir 118 can be a container in which at least a portion of the fluid 174 can be buffered inside or outside the gearbox housing 144 and can be discharged in a controlled fashion into the fluid sump 116 as a function of a cooling fluid pressure of a clutch cooling means.

(31) The gearbox 110 can comprise at least one actuator or controller 146. The actuator 146 can be connected to the fluid supply system 112, in particular to the valve 126, via at least one interface 148.

(32) The actuator 146 can comprise at least one control output 150. The gearbox 110 can be configured in such a way that the control output 150 simultaneously controls the pump 114 and the first fluid outflow 120, for example the valve 126.

(33) The gearbox 110 and/or the fluid supply system 112 can in particular be configured in such a way that in the event of a failure of the actuator 146 the fluid reservoir 118 runs empty. For example the orifice 130 of the second fluid outflow 128 can always be at least partially opened, and/or in the event of failure the orifice 130 of the first fluid outflow 120 and/or the orifice 130 of the second fluid outflow 128 can be at least partially opened, preferably without active actuation.

(34) In order to achieve an optimum function at different temperatures and/or with different viscosities of the fluid 174, it is possible, for example, to make use of a temperature model. For example, the actuator 146 can comprise a temperature model.

(35) FIG. 1 shows in particular, an exemplary embodiment of the device according to the invention, in which exemplary embodiment the valve 126 can preferably be a directional control valve 152 and/or a flap valve, particularly preferably an actuable directional control valve 152. The directional control valve 152 can be configured, in particular, in such a way that in the case of a high ram pressure in a clutch cooling oil line 154, in particular in the case of a large clutch cooling oil volume flow, the directional control valve 152 is opened, in particular in such a way that a volume of oil which is stored in the fluid reservoir 118 can be discharged and/or runs out from the fluid reservoir 118 into the fluid sump 116 and can be made available as quickly as possible there, for example for the pump which can preferably be configured as a cooling oil pump.

(36) FIG. 1 shows, in particular, a basic illustration of an actuable or controllable fluid reservoir 118.

(37) FIG. 2 shows a schematic partial illustration of a second exemplary embodiment of a gearbox 110 according to the invention. The second exemplary embodiment of a gearbox 110 according to the invention can be at least partially configured like the first exemplary embodiment.

(38) The exemplary embodiment illustrated in FIG. 2 can, in particular have at least one electrically commutated electric motor which is configured to pump, with the pump 114, fluid 174 from the fluid sump 116 via the filter 142 and a rotational bushing 156 to the clutch, in particular for cooling the clutch 122, but alternatively or additionally for actuating the clutch 122.

(39) The valve 126 can be, in particular, an actuable valve 158. The fluid reservoir 118 can in this exemplary embodiment be filled by sprayed fluid 140. For example, the fluid reservoir 118 can be filled by sprayed fluid which can be generated by at least one gear wheel set 160 and/or by the clutch 122. The filter 142 can serve, in particular, for filtering the fluid 174.

(40) FIG. 3 shows a schematic partial illustration, in particular a hydraulic diagram, of a third exemplary embodiment of a gearbox 110 according to the invention, in particular of an actuable fluid reservoir 118 of the gearbox 110 according to the invention. The third exemplary embodiment of the gearbox 110 according to the invention can be configured at least partially like the first exemplary embodiment of the gearbox 110 according to the invention and/or like the second exemplary embodiment of the gearbox 110 according to the invention.

(41) A pressure Δp in a supply line leading to the clutch 162 can usually be determined by a hydraulic resistance R.sub.v of the subsequent components, for example by the hydraulic resistance of the rotational bushing 156 and/or of the longitudinal section as far as the clutch 122, for example by the relationship Δp=R.sub.v*I.sub.v, where I.sub.v is a volume flow.

(42) The hydraulic resistance R.sub.v can depend on at least two operating parameters, for example on the volume flow I.sub.v, in particular on the volume flow through the subsequent components such as, for example, the clutch cooling fluid volume flow and the viscosity of the fluid 174, in particular of the gearbox fluid. The viscosity can usually depend on the temperature, such as is illustrated by way of example in FIG. 6. FIG. 6 shows, in particular, a typical profile of a kinematic viscosity ν in mm.sup.2/s of a gearbox fluid as a function of a temperature T in ° C.

(43) If, for example, the valve 126, which is, in particular, a releasable valve, were to be set to a fixed pressure, in particular a pressure value, for example a threshold value for a pressure and/or an opening pressure, this opening pressure could already be reached in the case of cold fluid 174 at a relatively low volume flow, in particular a lower feed volume flow than in the case of a warm fluid 174. In the case of a very low kinematic viscosity, in particular in the case of a low oil viscosity, for example as a result of a high temperature, the opening pressure could possibly no longer be reached at all.

(44) This problem can be at least partially solved or mitigated by virtue of the fact that, for example, the valve 126 can be a temperature-dependent valve 164 and/or at least one temperature model is used and/or by virtue of the fact that the valve 126 can be triggered by means of electrical activation.

(45) FIG. 4 shows a schematic partial illustration of a fourth exemplary embodiment of a gearbox 110 according to the invention. The fourth exemplary embodiment of a gearbox 110 according to the invention can be configured at least partially like the other exemplary embodiments, in particular like the first exemplary embodiment.

(46) The fourth exemplary embodiment can comprise, in particular, a valve which can be triggered by means of electrical activation. The fourth exemplary embodiment can, as is illustrated in FIG. 4, comprise, in particular, an actuable valve 158, for example an actuable discharge valve, in particular with electrical activation and at least one sensing device 132. The valve 126 can preferably be activated by evaluation of the method of functioning of the motor, preferably of the electric motor, by means of the sensing device 132.

(47) The valve 126, in particular the discharge valve, can be triggered, in particular, indirectly, in particular by means of the electrical activation. The valve 126 and/or the first fluid outflow 120 can, in particular, be actuable by evaluating the rotational speed of the pump 114 and/or of the motor, in particular of the electric pump motor 124, and/or by evaluating the rotational direction of the pump 114 and/or of the motor, in particular of the electric pump motor 124.

(48) The pump 114 can comprise, in particular, at least one reversal ring 166, as illustrated in FIGS. 7 and 8. The pump 114 can comprise at least a first opening 168 and at least a second opening 170. The first opening 168 can preferably be an intake opening. The second opening 170 can preferably be an outflow opening. The pump 114, in particular an electromagnetically driven cooling oil pump, can preferably comprise at least one pump wheel set 172, preferably when an evaluation of the rotational direction of the pump 114 is used.

(49) The pump 114, in particular the pump wheel set 172, can configured in such a way that a pump function of the electric motor, in particular from the fluid sump 116 to the clutch 112, can be maintained even given a changing rotational direction of the pump, in particular the drive rotational direction, in such a way that a direction of a fluid flow is therefore preferably not reversed if the rotational direction of the pump changes.

(50) The pump 114 can be, in particular a pump 114 as described in the German Patent Application by the Applicant of the present application which was published after the priority date of the present document and has the number DE 10 2013 110 400.2 or in DE 10 2011 122 642 A1. The reversal ring 166 can, in particular, be configured in such a way that the pump direction can be maintained even given a change of rotational direction of the pump 114, in particular a change in drive rotational direction.

(51) FIG. 5 shows a schematic partial illustration of a fifth exemplary embodiment of a gearbox 110 according to the invention. The fifth exemplary embodiment of a gearbox 110 according to the invention can be configured at least partially like the other exemplary embodiments. The valve 126 can have, for example, at least one temperature-dependent element, for example at least one element with a temperature-dependent spring constant, in particular in order to permit adaptation of a pressure for opening the valve 126, for example an opening pressure, to a temperature-dependent viscosity of the fluid 174, in particular of the cooling oil. The element with a temperature-dependent spring constant can comprise, for example, at least one bimetal spring. The valve 126 can, for example, have at least one bimetal spring alternatively or additionally to a normal, essentially temperature-independent spring. The valve 126 can be, for example, a thermostat valve and/or the valve 126 can comprise at least one thermostat valve. The fifth exemplary embodiment can comprise as valve 126, in particular, a temperature-dependent valve 164. The temperature-dependent valve 126 can be, for example, an actuable discharge valve with a temperature-dependent pressure threshold.

(52) In a further aspect of the present invention, a method for operating the gearbox 110 according to the invention is proposed as described above. The gearbox 110 comprises at least one fluid supply system 112. The fluid supply system 112 comprises at least one pump 114. The fluid supply system 112 comprises at least one fluid sump 116. The fluid supply system 112 comprises at least one fluid reservoir 118. The fluid reservoir 118 comprises at least a first fluid outflow 120 leading into the fluid sump 116. The first fluid outflow 120 is controlled as a function of a state variable.

(53) The gearbox 110 can comprise at least one controller/actuator 146. The actuator 146 can be configured to carry out the method according to the invention. The method can be executed, for example, at least partially by the actuator 146.

LIST OF REFERENCE NUMBERS

(54) 110 Gearbox 112 Fluid supply system 114 Pump 116 Fluid sump 118 Fluid reservoir 120 First fluid outflow 122 Clutch 124 Pump motor 126 Valve 128 Second fluid outflow 130 Orifice 132 Sensing device 134 Pressure sensor 136 Rotational speed sensor 138 Rotational direction sensor 140 Sprayed fluid 142 Filter 144 Gearbox housing 146 Controller/Actuator 148 Interface 150 Control output 152 Directional control valve 154 Clutch cooling fluid line 156 Rotational bushing 158 Actuable valve 160 Gear wheel set 162 Supply line to the clutch 164 Temperature dependent valve 166 Reversal ring 168 First opening 170 Second opening 172 Pump wheel set 174 Fluid