JP6288124B2 - Power transmission device for vehicle - Google Patents

Description

  The present invention relates to a power transmission device that transmits power from a drive source of a vehicle.

  Various power transmission devices including a transmission are used in a vehicle that travels by receiving power supplied from a power source such as an engine. In a power transmission device, oil is generally used for lubricating and driving internal component parts. Oil has the property that the viscosity increases when the temperature decreases. However, since the performance such as lubrication deteriorates when the viscosity increases, it is desirable to maintain the temperature of the oil at a certain level.

  For example, Patent Document 1 below discloses a toroidal continuously variable transmission which is a kind of automatic transmission. In this continuously variable transmission, a jacket is formed outside the case that houses the transmission mechanism and oil (hydraulic oil), and a high-temperature heat medium liquid heated by a heater is supplied to the jacket. Yes.

Japanese Patent No. 3994661

  According to the continuously variable transmission of Patent Document 1, the oil used in the case is indirectly warmed by warming the case with the high-temperature heat medium liquid. There is an advantage that the temperature can be quickly raised.

  However, in the technique of Patent Document 1, it is necessary to separately provide components such as a heater for heating the heat medium liquid and a pump for supplying and discharging the heat medium liquid, and the problem is that the structure is complicated and the cost is unavoidable. was there. Further, immediately after the start-up when the heating by the heater is not completed, there is a problem that the temperature of the oil is low and the performance of the continuously variable transmission is lowered.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vehicle power transmission device that can keep oil warm with a simple configuration.

  In order to solve the above problems, a vehicle power transmission device according to the present invention includes a power transmission mechanism that transmits power input from a power source of a vehicle to a predetermined output member, the power transmission mechanism, and the mechanism. An inner case that contains oil supplied to the inside, an outer case that is provided so as to cover the inner case from the outside, and that forms an airtight space between the inner case and the pressure in the airtight space. And a changeable pressure changing means. (Claim 1)

  In the present invention, the oil can be used for various purposes. For example, the oil may be an oil (lubricating oil) for lubricating various component parts included in the power transmission mechanism. It may be oil (hydraulic oil) for driving components by hydraulic pressure.

  According to the present invention, since the airtight space is formed between the inner case and the outer case, and the pressure in the airtight space can be changed by the pressure changing means, for example, the pressure in the airtight space when the vehicle is parked By reducing the temperature, heat transfer through the airtight space can be inhibited, and the power transmission mechanism and the temperature of the oil can be suppressed from being reduced by the influence of outside air. As a result, even when the vehicle is driven on the next day after parking, for example, the oil temperature is already higher than the outside air at the start of driving. It takes a short time to increase the temperature to a temperature suitable for use as hydraulic oil, and the performance of the power transmission device can be ensured satisfactorily.

  Moreover, according to the present invention that suppresses the temperature drop by adjusting the pressure in the hermetic space, the temperature of the oil immediately after the start of traveling of the vehicle is maintained at a high temperature, unlike the case where, for example, the oil that has once been cooled is heated by the heater Therefore, there is an advantage that a rational heat retaining structure with little thermal loss can be constructed with a simple configuration.

  In this invention, Preferably, the said pressure change means has a function to reduce the pressure in the said airtight space as the temperature of the said airtight space falls (Claim 2). Further, as a specific example of the pressure changing means having such a function, when the pressure in the airtight space is larger than a predetermined value, the airtight space and the outer space of the outer case are communicated with each other (opened). It is preferable to use a check valve that shuts off (closes) communication between the airtight space and the external space when the pressure is equal to or lower than the predetermined value.

  According to this configuration, for example, when the temperature of the airtight space rises as the vehicle travels, air flows from the airtight space to the external space through the opened check valve. As a result, the pressure in the airtight space is affected by the temperature rise. It is maintained at a constant value. On the other hand, the temperature of the airtight space decreases during parking after traveling, but at this time the check valve is closed so that air does not enter the airtight space from the external space, so the pressure in the airtight space Gradually decreases with decreasing temperature. As described above, when the pressure in the airtight space is reduced, heat transfer between the power transmission mechanism and the outside air performed through the airtight space is inhibited, so even if the temperature of the outside air is considerably low, the power transmission mechanism The oil temperature is maintained at a high temperature for a relatively long period of time.

  Further, since it is only necessary to provide a check valve, the power transmission mechanism and the oil can be kept warm with a simple and low-cost configuration without consuming special power.

  The pressure changing means may be an air pump that sucks air from the airtight space so that the pressure in the airtight space is lower when the temperature of the oil is low than when it is high (Claim 4).

  According to this configuration, the airtight space is depressurized by the air pump as the temperature of the oil decreases, so heat transfer through the airtight space can be inhibited. During parking of the vehicle, the temperature of the power transmission mechanism and the oil can be maintained at a relatively high temperature.

  In this invention, Preferably, the heat exchanger for adjusting the temperature of the said oil is arrange | positioned in the said airtight space (Claim 5).

  According to this configuration, the heat exchanger can be arranged by effectively using the airtight space, and an increase in the size of the power transmission device is suppressed while an additional outer case for forming the airtight space is provided. can do.

  In the above configuration, more preferably, the inner case is formed in a cylindrical shape extending along the axial direction of the power transmission mechanism, and a pipe for supplying a heat exchange medium to the heat exchanger is provided in the inner case. It arrange | positions so that it may derive | lead-out from the axial direction edge part (Claim 6).

  According to this configuration, since it is not necessary to arrange the pipe so as to penetrate the outer case, a measure such as additionally installing a seal member or the like in the penetrating portion can be eliminated, and the structure can be simplified.

  Further, when there is a connecting member that communicates the components in the inner case with the outside, it is preferable that the connecting member is also arranged so as to be led out from the axial end of the inner case. ).

  According to this configuration, since the connecting member does not penetrate the outer case, the structure can be simplified.

  The present invention is applicable to various power transmission devices for vehicles, and preferred examples thereof include an automatic transmission or a manual transmission. In this case, the power transmission mechanism is a transmission mechanism that transmits the power input from the power source to the output shaft on the wheel side while shifting the speed.

  The present invention can also be applied to a differential device. In this case, the power transmission mechanism is a differential mechanism that transmits the power input from the power source to the left and right wheels.

  As described above, according to the vehicle power transmission device of the present invention, it is possible to keep oil warm with a simple configuration.

It is a figure showing a 1st embodiment of the present invention and is a side sectional view of an automatic transmission. It is a figure for demonstrating the modification of the said 1st Embodiment. It is a figure for demonstrating another modification of the said 1st Embodiment. It is a figure which shows 2nd Embodiment of this invention, and is side surface sectional drawing which extracts and shows only the inner side case and outer side case of an automatic transmission. It is a figure which shows 3rd Embodiment of this invention, and is a sectional side view of an automatic transmission. It is a figure which shows 4th Embodiment of this invention, and is a plane sectional view of a differential gear.

<First Embodiment>
First, an example in which the present invention is applied to an automatic transmission that is one of vehicle power transmission devices will be described as a first embodiment. FIG. 1 is a side sectional view of the automatic transmission according to the first embodiment. The automatic transmission shown in this figure transmits power input from an engine (not shown) provided as a power source of the vehicle to the wheel side while shifting. Specifically, the automatic transmission includes a transmission mechanism 1 that transmits power between an input shaft 100 that is an engine crankshaft and a wheel-side output shaft 101 that is arranged coaxially with the input shaft 100, and the transmission mechanism 1. A valve body 2 disposed below the transmission mechanism 1 for supplying and discharging various oils (operating oil, lubricating oil, etc.), an inner case 3 that accommodates the transmission mechanism 1 and the valve body 2 therein, and an inner side An outer case 4 is provided so as to further cover the case 3 from the outside. In the following description, the side closer to the input shaft 100 is referred to as “front” of the automatic transmission and the “rear” of the automatic transmission closer to the output shaft 101.

  The transmission mechanism 1 includes a torque converter 10 that transmits the rotation of the input shaft 100 via ATF oil (working fluid), a turbine shaft 11 that extends in the front-rear direction as an output shaft of the torque converter 10, and a periphery of the turbine shaft 11. And a planetary gear mechanism 12 that transmits the rotation input from the turbine shaft 11 to the output shaft 101 while shifting the speed.

  The torque converter 10 has a pump case 10a that rotates integrally with the input shaft 100, and is disposed inside the pump case 10a so as to be opposed to the pump impeller in the front-rear direction and the pump impeller formed integrally with the pump case 10a. The turbine runner and a stator (all not shown) arranged between the pump impeller and the turbine runner have a conventionally known structure. The turbine runner is coupled to the turbine shaft 11, and the turbine shaft 11 is disposed so as to extend rearward from the pump case 10 a toward the output shaft 101. The pump case 10a is filled with ATF oil, and the rotation of the pump case 10a and the pump impeller is transmitted to the turbine runner and the turbine shaft 11 via the ATF oil during operation of the engine in which the input shaft 100 rotates. It has become so.

  The planetary gear mechanism 12 is not shown in detail, but a plurality of planetary gear sets (sun gear, planetary gear, ring gear), a plurality of connecting members that connect specific elements of each planetary gear set, and these planetary gear sets and connecting members. And a plurality of frictional engagement elements (clutch and brake) that are engaged or released to switch the power transmission path realized by the above. Then, the intermittent engagement of each frictional engagement element is controlled by the hydraulic pressure of the hydraulic oil supplied from the valve body 2, so that a desired gear ratio according to the vehicle speed or the like is achieved.

  The inner case 3 is made of a metal such as cast iron or cast steel, and is formed in a hollow cylindrical shape that extends along the front-rear direction (the axial direction of the speed change mechanism 1) as a whole. Specifically, the inner case 3 is formed so as to surround the outer periphery of the planetary gear mechanism 12 and to extend further forward while expanding from the front end of the main body portion 21. 10 and a lower cover portion 23 that is attached so as to close the opening formed in the lower surface of the main body portion 21 and cover the valve body 2 from below.

  The front end of the front extension 22 is an open end having a large opening S, and a front end flange 22a is formed around the opening S. The automatic transmission is fixed to the engine by the front end flange 22a being coupled to the engine cylinder block or the like.

  A front partition 25 is attached to the boundary between the front extension 22 and the main body 21 from the front. The front partition 25 provides a space for the torque converter 10 and a space for the planetary gear mechanism 12. It is partitioned in the front-rear direction.

  A rear partition wall 26 having a hole H through which the output shaft 101 passes is integrally formed at the rear end of the main body 21. Further, a rear end flange 21a for connecting a second flange 4b of the outer case 4 described later is formed on the outer periphery of the main body portion 21 located slightly forward of the rear partition wall 26.

  A notch C is formed at the lower rear end of the main body 21. The notch C is formed so as to partially remove the wall surface of the main body 21 (including a part of the rear partition wall 26) below the output shaft 101.

  A connector 40 is attached to the lower end of the rear end of the main body 21 so as to close the notch C. That is, the connector 40 is attached to the lower part of the rear end of the main body portion 21 with a part thereof entering the inside of the inner case 3 through the notch C. Various electrical wirings 41 are connected to the connector 40 from inside and outside the automatic transmission (however, only the wiring outside the automatic transmission is shown in FIG. 1). Thus, control signals for controlling the automatic transmission are transmitted / received and power is supplied. The electrical wiring 41 corresponds to an example of a “communication member” in the claims.

  The output shaft 101 is disposed on the rear side of the turbine shaft 11 so as to extend coaxially with the turbine shaft 11, and extends over the inside and outside of the inner case 3 through the hole H of the rear partition wall 26. The front end portion of the output shaft 101 is coupled to a predetermined output member (not shown) provided at the rear end portion of the planetary gear mechanism 12 inside the inner case 3. The rotation input from the turbine shaft 11 to the planetary gear mechanism 12 is output to the output member while being shifted by the planetary gear mechanism 12 and transmitted to the output shaft 101.

  A parking gear 101 a is fitted on the front end portion of the output shaft 101. The parking gear 101a is for locking the output shaft 101 when the position (shift position) of a shift lever (not shown) provided in the vehicle interior is in the P range (parking range).

  The parking gear 101 a can be engaged with a lock lever 42 introduced from the outside of the inner case 3. The lock lever 42 is disposed so as to extend from the rear of the inner case 3 to the vicinity of the parking gear 101a through the notch C, and is attached to the parking gear 101a so as to be detachable in the radial direction. When the shift position is switched to the P range, the output lever 101 is locked by driving the lock lever 42 and engaging the parking gear 101a accordingly. The lock lever 42 corresponds to an example of a “contact member” in the claims.

  The outer case 4 is an integral molded product made of, for example, a synthetic resin, and is formed in a hollow cylindrical shape having an outer diameter that is slightly larger than that of the inner case 3 as a whole. Specifically, the outer case 4 is formed so that the outer diameter is slightly larger toward the front side in accordance with the outer diameter of the inner case 3, and has a first flange 4a projecting radially outward at the front end, The rear end has a second flange 4b projecting inward in the direction.

  The first flange 4a of the outer case 4 is coupled to the front end flange 22a of the inner case 3 from behind via a fastening member such as a bolt. A seal member 31 made of an O-ring or the like is attached to the coupling surface between the first flange 4a and the front end flange 22a.

  The second flange 4b of the outer case 4 is coupled to the rear end flange 21a of the inner case 3 from behind via a fastening member such as a bolt. A seal member 32 made of an O-ring or the like is attached to the coupling surface between the second flange 4b and the rear end flange 21a.

  Here, the reason why the sealing members 31 and 32 are used on the coupling surface between the outer case 4 and the inner case 3 is that air does not enter the gap space between the outer case 4 and the inner case 3 from the outside. This is to prevent it from occurring. That is, in the present embodiment, the gap space between the outer case 4 and the inner case 3 is an airtight space X that is sealed so that outside air does not enter.

  A check valve 30 as pressure changing means is attached to the lower wall portion of the outer case 4. The check valve 30 is configured to open when the pressure in the airtight space X is greater than atmospheric pressure, and to close when the pressure is less than atmospheric pressure. That is, when the pressure in the airtight space X exceeds atmospheric pressure and the check valve 30 is opened, the airtight space X and the space Y outside the outer case 4 (hereinafter referred to as the external space Y) communicate with each other. When the pressure in the airtight space X becomes equal to or lower than the atmospheric pressure and the check valve 30 is closed, the communication between the airtight space X and the external space Y is blocked.

  Since the pressure in the external space Y is normally atmospheric pressure, when the pressure in the airtight space X exceeds atmospheric pressure, the check valve 30 is opened accordingly (the airtight space X and the external space Y). The air flows from the airtight space X having a relatively high pressure to the external space Y through the check valve 30, and the pressure in the airtight space X is reduced to atmospheric pressure. And when it falls to atmospheric pressure, while the air flow stops naturally, the non-return valve 30 is closed. However, since the check valve 30 is kept closed at atmospheric pressure or lower, even if the pressure in the airtight space X subsequently drops to less than atmospheric pressure (that is, even if the pressure magnitude relationship is reversed) Air does not flow from the space Y to the airtight space X, and the pressure in the airtight space X is maintained below atmospheric pressure. As described above, in this embodiment, the check valve 30 is provided in the outer case 4, so that the pressure in the airtight space X is prohibited from exceeding atmospheric pressure, but the pressure in the airtight space X is It is allowed to be below atmospheric pressure.

  In the vicinity of the check valve 30 in the airtight space X, an ATF cooler 45 (corresponding to the “heat exchanger” in the claims) for adjusting the temperature of the ATF oil supplied to the torque converter 10 is disposed. ing. Connected to the ATF cooler 45 is a cooling water pipe 46 for supplying and discharging the engine cooling water to and from the ATF cooler 45 as a heat exchange medium. In the ATF cooler 45, the temperature is adjusted so that the ATF oil is within a certain temperature range by heat exchange with the cooling water.

  The cooling water pipe 46 is disposed so as to penetrate the attachment portion 22 b formed in the lower portion of the front extension portion 22 in the inner case 3, and the penetrating tip portion is connected to the ATF cooler 45. A seal member 47 made of rubber sheet packing or the like for preventing air leakage to the airtight space X is attached to a connection portion between the cooling water pipe 46 and the ATF cooler 45. Such a cooling water pipe 46 is led out through the opening S at the front end of the inner case 3 and is connected to a cooling water supply source (not shown).

  As described above, in the automatic transmission according to the first embodiment, when the airtight space X is formed between the inner case 3 and the outer case 4, and the pressure in the airtight space X is larger than the atmospheric pressure. A check valve 30 is attached to the outer case 4 and is opened when the pressure is less than atmospheric pressure. According to such a configuration, the inside of the airtight space X can be depressurized as the temperature decreases, and thus there is an advantage that the transmission mechanism 1 and the oil can be kept warm in a low temperature environment.

  That is, the automatic transmission can exhibit the best performance in a state where the oil used in the transmission mechanism 1 has risen to an appropriate temperature (for example, around 80 ° C.). However, even if the oil temperature rises sufficiently as the vehicle travels (operation of the engine and automatic transmission), the vehicle is parked afterwards (that is, when the vehicle is left in the ignition-off state). In the meantime, the temperature of the oil gradually decreases with time. In particular, in a cold region where the outside air temperature is below freezing point, for example, the temperature of the oil greatly decreases during the night when the vehicle is not used. This means that the viscosity of the oil increases and the required function (function as hydraulic oil or lubricating oil) decreases. Of course, when the vehicle travels again, the oil temperature rises again, but it takes a considerable amount of time to raise the oil temperature once it has dropped significantly to the appropriate temperature. Can not be secured.

  On the other hand, in the first embodiment, for example, when the temperature of the airtight space X is sufficiently increased (for example, to around 80 ° C.) as the vehicle travels, the valve is opened by receiving a pressure higher than the atmospheric pressure. As a result of air flowing from the airtight space X to the external space Y through the check valve 30, the pressure in the airtight space X is maintained at a constant value (atmospheric pressure) regardless of the temperature rise. On the other hand, the temperature of the airtight space X decreases during parking after traveling. At this time, the check valve 30 is closed so that air does not enter the airtight space X from the external space Y. The pressure in the space X gradually decreases as the temperature decreases and is reduced to a negative pressure (less than atmospheric pressure). In particular, if the vehicle is parked in a cold district as described above, the degree of negative pressure in the airtight space X is further increased by condensation or freezing of water vapor contained in the airtight space X. As described above, when the pressure in the airtight space X becomes negative, heat transfer between the transmission mechanism 1 and the outside air performed through the airtight space X is hindered, so even if the temperature of the outside air is considerably low, the speed change is performed. The temperature of the mechanism 1 and oil is maintained at a high temperature for a relatively long period. As a result, even when the vehicle is driven on the next day after parking, for example, the oil temperature is already sufficiently higher than the outside air at the start of the driving. The time required for the lift is short, and the performance of the automatic transmission can be ensured satisfactorily.

  Moreover, since only the check valve 30 needs to be provided in the outer case 4, unlike the case where the temperature of the oil is raised by, for example, an electric heater, the electric power is not consumed specially and the configuration is simple and low cost. The transmission mechanism 1 and the oil can be kept warm.

  On the other hand, when a sufficient amount of time has elapsed after the vehicle starts running and the automatic transmission has been warmed up (oil temperature rise), the pressure in the airtight space X again rises to near atmospheric pressure. In such a state where the pressure is recovered, heat transmission (heat radiation from the transmission mechanism 1) is easily performed between the transmission mechanism 1 and the outside air, so that the transmission mechanism 1 and the oil can be appropriately cooled. . Therefore, the heat retaining structure according to the first embodiment is advantageous in terms of cooling at a high temperature, unlike a case where, for example, a heat insulating material is simply attached to the transmission case.

  In the first embodiment, since the ATF cooler 45 for adjusting the temperature of the ATF oil is disposed in the airtight space X, the airtight space X can be used effectively and the airtight space X is formed. Although the outer case 4 is additionally provided, the automatic transmission can be prevented from increasing in size.

  Further, in the first embodiment, the cooling water pipe 46 that supplies the ATF cooler 45 with the cooling water that is a medium for heat exchange is led out to the outside through the opening S at the front end (axial end) of the inner case 3. Therefore, unlike the case where the cooling water pipe 46 is led to the outside from below (see a modification of FIG. 2 described later), there is no need to arrange the cooling water pipe 46 so as to penetrate the outer case 4. Measures such as adding a seal member or the like to the penetrating portion can be made unnecessary, and the structure can be simplified.

  In the first embodiment, the lock lever 42 for locking the output shaft 101 when the shift range is the P range is provided outside through the notch C at the rear end (axial end) of the inner case 3. In addition, since the electrical wiring 41 for transmission / reception of control signals and power feeding is led out to the outside through the notch C, the lock lever 42 and the electrical wiring 41 are arranged so as to penetrate the outer case 4. There is no need to provide a structure, and the structure can be simplified.

  In the first embodiment, the cooling water pipe 46 of the ATF cooler 45 is led out to the outside through the opening S at the front end of the inner case 3. For example, as shown in FIG. After the outer case 4 is attached so as to cover the range excluding, a cooling water pipe 46 ′ may be disposed so as to penetrate the front extending portion 22 that is not covered by the outer case 4. That is, in the example of FIG. 2, a mounting flange 22 c that protrudes radially outward is formed at the rear portion of the front extending portion 22, and the first flange 4 a ′ at the front end of the outer case 4 is formed on the mounting flange 22 c. The seal member 31 ′ is coupled from the rear with the seal member 31 ′ interposed therebetween. Thereby, the outer case 4 is attached to the inner case 3 in a state in which the front extending portion 22 in a portion in front of the attachment flange 22c is not covered. An ATF cooler 45 is disposed inside the front extension 22, and a cooling water pipe extends downward (radially outward) from the ATF cooler 45 and penetrates the peripheral wall of the front extension 22. 46 'is provided. Even in this case, since the cooling water pipe 46 ′ does not penetrate the outer case 4, the airtightness of the airtight space X can be ensured with a simple configuration.

  Of course, in the layout as in the first embodiment (FIG. 1) or the modified example of FIG. 2, the cooling water pipe 46 (46 ′) or the ATF cooler 45 is provided in the front extending portion 22 in which the torque converter 10 is accommodated. Therefore, in some cases, interference between the cooling water pipe 46 (46 ′) or the ATF cooler 45 and the torque converter 10 may be unavoidable. Therefore, in such a case, as shown in FIG. 3, the cooling water pipe 46 ″ is disposed so as to extend downward (outward in the radial direction) from the ATF cooler 45 so as to penetrate the peripheral wall of the outer case 4. However, in this case, in order to secure the airtightness of the airtight space X, it is desirable to attach the seal member 48 to the penetrating portion of the cooling water pipe 46 ″.

Second Embodiment
In the first embodiment, the outer case 4 made of a hollow cylindrical integral molded product that is slightly larger than the inner case 3 is prepared, and the outer case 4 is attached to the inner case 3 so as to be extrapolated from the rear. The structure of the outer case 4 is not limited to this, and may be a two-part structure, for example. Next, an example will be described as a second embodiment.

  FIG. 4 shows the inner case 3 and the outer case 54 used in the automatic transmission according to the second embodiment of the present invention (the transmission mechanism is not shown). As shown in this figure, the outer case 54 of the second embodiment has a first divided body 54A and a second divided body 54B that are detachably coupled in the vertical direction. Each of the divided bodies 54A and 54B is formed in a substantially semicircular arc shape in a sectional view, and the upper half of the inner case 3 is covered with the first divided body 54A, and the lower half of the inner case 3 is the second divided body 54B. Covered by. Flanges 54c and 54d are formed on the left and right side portions of the first divided body 54A and the second divided body 54B, respectively, and these flanges 54c and 54d are brought into contact with each other and connected by a fastening member such as a bolt. Thus, a substantially cylindrical outer case 54 that is slightly larger than the inner case 3 as a whole is formed.

  Further, in order to ensure the airtightness of the airtight space X formed between the outer case 54 and the inner case 3, a seal member (not shown) made of rubber sheet packing or the like is provided between the flanges 54c and 54d. Are attached, and the contact portion between the inner peripheral surface of the front end portion of the outer case 54 and the outer peripheral surface of the inner case 3 (front extending portion 22), and the inner peripheral surface of the rear end portion of the outer case 54 and the inner case 3 Seal members 55 and 56 each made of an O-ring or the like are attached to a contact portion with the outer peripheral surface of (main body portion 21). And in order to make the airtight space X at the time of temperature fall into a negative pressure, the same check valve 30 as the said 1st Embodiment is attached to the 2nd division body 4B of the outer case 4. FIG.

<Third Embodiment>
In the first embodiment, the check valve 30 is provided in the outer case 4 so that the pressure in the airtight space X at the time of temperature drop is lowered, thereby keeping the transmission mechanism 1 and the oil warm. Sometimes, the pressure changing means for making the airtight space X into a negative pressure is not limited to the check valve 30 and various alternatives are possible. Next, an example will be described as a third embodiment.

FIG. 5 shows an automatic transmission according to a third embodiment of the present invention. As shown in this figure,
In the third embodiment, an air pipe 61 extending from the air pump 60 is connected to the peripheral wall (here, the lower wall portion) of the outer case 4. The air pump 60 has, for example, a rotating element (such as an impeller) that is driven to rotate in the forward or reverse direction by an electric motor, and selectively selects either air suction or air discharge according to the rotation direction. This is an executable pressure change means. The air pipe 61 extends from the air pump 60 so as to penetrate the lower wall portion of the outer case 4, and the tip of the air pipe 61 enters the airtight space X between the outer case 4 and the inner case 3. . A seal member 63 for securing the airtightness of the airtight space X is attached to the penetrating portion of the air pipe 61.

  The valve body 2 is provided with an oil temperature sensor SN1 that detects the temperature of oil supplied to the transmission mechanism 1 as hydraulic oil or lubricating oil. A pressure sensor SN <b> 2 that detects the pressure in the airtight space X is attached to the inner wall of the outer case 4. Values detected by the oil temperature sensor SN1 and the pressure sensor SN2 are input as electric signals to a control unit 70 (so-called TCM; Transmission Control Module) provided in the valve body 2. In order to transmit and receive such signals, the oil temperature sensor SN1 and the TCM 70 are connected to each other via the electric wiring 64 routed inside the valve body 2, and the electric wirings 65 and 66 and the connector 40 are connected to each other. The pressure sensor SN2 and the TCM 70 are connected to each other. Further, in order to control the air pump 60, the TCM 70 is connected to the air pump 60 via the electrical wirings 65 and 67 and the connector 40.

  The TCM 70 controls the air pump 60 so as to suck more air from the airtight space X as the temperature of the oil detected by the oil temperature sensor SN1 is lower, and decompresses the inside of the airtight space X. On the contrary, when the temperature of the oil rises, air is sent out from the air pump 60 to increase the pressure in the airtight space X.

  The above-described control is performed not only while the vehicle is traveling (that is, during ignition on) but also during parking of the vehicle (that is, during ignition off). However, while the vehicle is parked, in anticipation of the oil temperature decreasing over time, a sufficiently large amount of air is sucked from the airtight space X within a limited time after the ignition is turned off, and thereafter the air pump 60 is controlled. It is desirable to stop the operation in terms of reducing power consumption.

  According to the third embodiment as described above, the airtight space X is depressurized by the air pump 60 as the temperature of the oil supplied to the speed change mechanism 1 decreases. Thus, heat transfer between the transmission mechanism 1 and the outside air can be inhibited, and the temperature of the transmission mechanism 1 and the oil is maintained at a relatively high temperature during parking in a cold region, for example, as in the first embodiment described above. can do.

  Further, for example, in a situation where a vehicle is cruising on a highway in a cold region, the load of the engine and the automatic transmission is small, so that the oil temperature is lower than an appropriate value (around 80 ° C.) due to the influence of cold outside air. May also decrease. On the other hand, according to the third embodiment in which the air pump 60 is driven according to the temperature of the oil, the inside of the airtight space X is appropriately depressurized even when the temperature of the oil is lowered due to the above reasons. Thus, it is possible to keep the transmission mechanism 1 and the oil warm. On the contrary, when the temperature of the oil increases, the pressure in the airtight space X is increased, so that it is possible to avoid the transmission mechanism 1 and the oil from being excessively heated.

  In the third embodiment, a pump capable of both sucking and discharging air is used as the air pump 60. However, an air pump (vacuum pump) capable of only sucking air may be used. In this case, although the pressure in the airtight space X cannot be increased by using an air pump, a valve for communicating the airtight space X and the external space Y is provided in the outer case 4 separately. It is recommended to open the valve.

<Fourth embodiment>
In the first to third embodiments, the example in which the present invention is applied to an automatic transmission that is one of vehicle power transmission devices has been described. However, the present invention is not limited to an automatic transmission and is used for a vehicle. The present invention can be applied to various power transmission devices. Next, an example will be described as a fourth embodiment.

  In the fourth embodiment shown in FIG. 6, the present invention is applied to a vehicle differential. Specifically, the differential device of FIG. 6 is a so-called rear differential, and the rotation input from the engine and transmission (automatic transmission or manual transmission) (not shown) via the propeller shaft 110 is changed to the left and right wheels ( It is transmitted to the drive shafts 111 and 112 connected to the rear wheels.

  More specifically, the differential device includes a relay shaft 81 that is connected to the propeller shaft 110 so as to rotate integrally with the propeller shaft 110 and extends in the front-rear direction, and the rotation of the relay shaft 81 is changed to the left and right drive shafts 111 and 112. A differential mechanism 80 for transmitting to the inner side, an inner case 83 for accommodating the relay shaft 81 and the differential mechanism 80, and an outer case 84 provided so as to further cover the inner case 83 from the outside.

  The differential mechanism 80 transmits the rotation of the propeller shaft 110 (relay shaft 81) to the drive shafts 111 and 112 while allowing a difference in rotation between the left and right drive shafts 111 and 112 when the vehicle turns. It has a conventionally known structure that can be used, and has various gears (ring gear, pinion gear, side gear, etc.) meshed in a predetermined pattern. The differential mechanism 80 is filled with oil (lubricating oil) for lubricating the gear.

  The inner case 83 is formed in a hollow cylindrical shape so as to accommodate the differential mechanism 80. A front boss portion 85 having an opening for leading out the relay shaft 81 is formed at the front portion of the inner case 83, and the left and right drive shafts 111 and 112 are led out at the left and right side portions of the inner case 83. A left boss portion 86 and a right boss portion 87 having an opening for the purpose are formed.

  The outer case 84 has a shape similar to the inner case 83 as a whole, and is formed to be slightly larger than the inner case 83 so that the inner case 83 can be accommodated. Further, the outer case 84 has a front mouth portion 91 formed on the left side boss portion 85 and a left side boss portion 87 at positions corresponding to the front boss portion 85, the left side boss portion 86, and the right side boss portion 87, respectively. It has a mouth portion 92 and a right mouth portion 93. Seal members 94 to 96 made of O-rings or the like are attached to contact surfaces between the boss portions 85 to 87 and the mouth portions 91 to 93. Although not shown in detail, the outer case 84 of the fourth embodiment is composed of two divided bodies that are detachably coupled in the left-right direction. A seal member made of packing or the like is attached. As a result, an airtight space X ′ is formed between the outer case 84 and the inner case 83 so as to prevent outside air from entering.

  A check valve 90 is attached to the outer case 84. The check valve 90 is configured to open when the pressure in the airtight space X ′ exceeds the atmospheric pressure, and closes when the pressure in the airtight space X ′ falls below the atmospheric pressure, similarly to the check valve 30 of the first embodiment described above. Has been.

  According to the fourth embodiment as described above, the air in the airtight space X ′ is discharged to the outside through the check valve 90 at a high temperature, so that the temperature decreases thereafter (for example, while the vehicle is parked). The inside of the airtight space X ′ is decompressed. Thereby, the airtight space X can be made into a negative pressure, the heat transfer between the differential mechanism 80 and outside air can be inhibited, and the heat retention of the differential mechanism 80 and oil can be aimed at.

  As mentioned above, although preferable embodiment of this invention was described, the power transmission device for vehicles which can apply this invention is an automatic transmission (FIGS. 1-5) and differential apparatus (FIG. 6) which were illustrated by embodiment. For example, a manual transmission may be used.

1 Transmission mechanism (power transmission mechanism)
3 Inner case 4 Outer case 30 Check valve (pressure change means)
41 Electric wiring (communication member)
42 Lock lever (contact member)
45 ATF cooler (heat exchanger)
46 Cooling water piping (piping)
54 Outer case 60 Air pump (pressure changing means)
80 Differential mechanism (Power transmission mechanism)
X Airtight space X 'Airtight space Y External space

Claims (9)

A power transmission mechanism that transmits power input from a power source of the vehicle to a predetermined output side member;
An inner case that houses therein the power transmission mechanism and oil supplied to the mechanism;
An outer case provided so as to cover the inner case from the outside, and forming an airtight space with the inner case;
A vehicle power transmission device comprising: a pressure changing unit capable of changing a pressure in the airtight space. The vehicle power transmission device according to claim 1,
The power transmission device for a vehicle, wherein the pressure changing unit has a function of reducing the pressure in the airtight space as the temperature of the airtight space decreases. The vehicle power transmission device according to claim 2,
The pressure changing means causes the airtight space and the outer space of the outer case to communicate with each other when the pressure in the airtight space is greater than a predetermined value, and when the pressure is less than or equal to the predetermined value, A power transmission device for a vehicle, wherein the power transmission device is a check valve that blocks communication with the external space. The vehicle power transmission device according to claim 1,
The vehicle power, wherein the pressure changing means is an air pump that sucks air from the airtight space so that the pressure in the airtight space is lower when the temperature of the oil is low than when it is high. Transmission device. In the vehicle power transmission device according to any one of claims 1 to 4,
A power transmission device for a vehicle, wherein a heat exchanger for adjusting the temperature of the oil is disposed in the airtight space. The vehicle power transmission device according to claim 5,
The inner case is formed in a cylindrical shape extending along the axial direction of the power transmission mechanism,
A vehicle power transmission device, wherein a pipe for supplying a heat exchange medium to the heat exchanger is arranged so as to be led out from an axial end of the inner case. In the vehicle power transmission device according to any one of claims 1 to 6,
The inner case is formed in a cylindrical shape extending along the axial direction of the power transmission mechanism,
A vehicular power transmission device, wherein a connecting member that communicates a component in the inner case with the outside is disposed so as to be led out from an axial end of the inner case. In the vehicle power transmission device according to any one of claims 1 to 7,
The power transmission mechanism according to claim 1, wherein the power transmission mechanism is a transmission mechanism that transmits power input from the power source to an output shaft on a wheel side while shifting. In the vehicle power transmission device according to any one of claims 1 to 7,
The vehicle power transmission device, wherein the power transmission mechanism is a differential mechanism that transmits power input from the power source to left and right wheels.

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