JP2021042815A - Power transmission device - Google Patents

Abstract

To suppress changes in height on an oil level of an oil bath in a power transmission device.SOLUTION: A power transmission device 30 includes: a case 40 that forms an oil bath 41 capable of collecting a lubricant; a power transmission mechanism 30a that has a sprocket 31 at least partially immersed in the lubricant in the oil bath, and a sprocket 32 transmitting power to and from the sprocket 31 by a chain 21 wound between the sprocket 31 and the sprocket 32; and a chain guide 50 sliding with an outer peripheral surface of the chain 21. The chain guide 50 has an oil removing surface 52 inclined so as to gradually get close from an outer periphery side of the chain 21 to the outer peripheral surface of the chain 21, toward a traveling direction of the chain 21 during normal rotations.SELECTED DRAWING: Figure 3

Description

The present invention relates to a power transmission device.

Patent Document 1 describes a first sprocket partially submerged in oil stored in the lower part of an internal combustion engine body, a second sprocket, a chain hung on the first and second sprockets, and a chain and a slide. A power transmission mechanism for an internal combustion engine including a contacting chain guide is disclosed.

The chain guide of this power transmission mechanism has a guide portion that is in sliding contact with the outer peripheral surface of the chain, an extension portion that extends from the guide portion toward the inner peripheral direction of the chain, and an extension portion that faces the second sprocket. It has an oil drop part.

JP-A-2017-96391

However, although the oil dropping portion of Patent Document 1 can suppress the scattering of oil from the inner circumference of the chain, the oil is scattered on the outer circumference of the chain. As a result, the oil may be scattered in the power transmission mechanism, and the height of the oil level of the stored oil may change.

The present invention has been made in view of such technical problems, and an object of the present invention is to suppress a change in the oil level of an oil bath in a power transmission device.

According to an aspect of the present invention, the power transmission device includes a case of forming an oil bath in which lubricating oil is stored, a first sprocket in which at least a part of the lubricating oil is immersed in the lubricating oil in the oil bath, and the above. A power transmission mechanism having a second sprocket in which power is transmitted to and from the first sprocket by a chain wound around the first sprocket, and a chain guide that is in sliding contact with the outer peripheral surface of the chain. The power of the chain guide is characterized by having a first oil dropping surface that gradually inclines from the outer peripheral side of the chain toward the outer peripheral surface of the chain toward the traveling direction of the chain. A transmission device is provided.

In the above aspect, the lubricating oil scattered from the outer periphery of the chain is collected by the first oil drop surface. Since the first surface is inclined from the outer peripheral side of the chain toward the traveling direction of the chain, the collected lubricating oil can be moved along the first oil dropping surface and returned to the oil bath. As a result, it is possible to sufficiently suppress the scattering of the lubricating oil from the outer periphery of the chain and suppress the change in the oil level of the oil bath.

It is a schematic block diagram of the hybrid vehicle to which the power transmission device which concerns on embodiment of this invention is applied. It is a schematic diagram of the power transmission device which concerns on embodiment of this invention. It is an enlarged view of the main part which concerns on embodiment of this invention. It is a schematic diagram of the power transmission device which concerns on the modification of embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Hereinafter, with reference to FIGS. 1 to 3, the power transmission device 30 according to the embodiment of the present invention and the hybrid vehicle (hereinafter, simply referred to as “vehicle”) 100 to which the power transmission device 30 is applied will be described. ..

First, the overall configuration of the vehicle 100 will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a vehicle 100 to which the power transmission device 30 is applied.

The vehicle 100 includes a low-voltage battery 1, a high-voltage battery 2, an engine 3, a motor generator 4 (hereinafter, referred to as “MG4”), and a starter motor 5 (hereinafter, “SM5”) used for starting the engine 3. ), A starter generator 6 (hereinafter referred to as "SG6") used for power generation, assisting and starting the engine 3, a DC-DC converter 7, an inverter 8, and a mechanical oil pump as a hydraulic source. 9, the electric oil pump 10, the torque converter 11 constituting the transmission, the forward / backward switching mechanism 12, the stepless speed change mechanism 13 (hereinafter referred to as “CVT 13”), the differential mechanism 14, the drive wheels 18, and so on. It includes a controller 20 and.

The low voltage battery 1 is a lead acid battery having an output voltage of DC12V. The low-voltage battery 1 is connected to the low-voltage circuit 16 together with electrical components 15 (automatic driving camera 15a and sensor 15b, navigation system 15c, audio 15d, air conditioner blower 15e, etc.) that operate at SM5 and 12V. The low voltage battery 1 may be a lithium ion battery having an output voltage of 12 V.

The high-voltage battery 2 is a DC48V lithium-ion battery having a higher output voltage than the low-voltage battery 1. The output voltage of the high voltage battery 2 may be lower or higher than this, and may be, for example, 30V or 100V. The high-voltage battery 2 is connected to the high-voltage circuit 17 together with the MG4, SG6, inverter 8, electric oil pump 10, and the like.

The low-voltage circuit 16 and the high-voltage circuit 17 are connected via a DC-DC converter 7. The DC-DC converter 7 has a boosting function that boosts 12V of the low-voltage circuit 16 to 48V and outputs 48V to the high-voltage circuit 17, and steps down 48V of the high-voltage circuit 17 to 12V to 12V to the low-voltage circuit 16. It has a step-down function to output. As a result, the DC-DC converter 7 can output a voltage of 12 V to the low voltage circuit 16 regardless of whether the engine 3 is running or stopped. When the remaining capacity of the high-voltage battery 2 is low, the 12V of the low-voltage circuit 16 can be boosted to 48V and output to the high-voltage circuit 17 to charge the high-voltage battery 2.

The engine 3 is an internal combustion engine that uses gasoline, light oil, or the like as fuel, and its rotation speed, torque, or the like is controlled based on a command from the controller 20.

The torque converter 11 is provided on the power transmission path between the engine 3 and the forward / backward switching mechanism 12, and transmits power via a fluid. Further, the torque converter 11 can improve the power transmission efficiency of the driving force from the engine 3 by engaging the lockup clutch 11a when the vehicle 100 is traveling at a predetermined lockup vehicle speed or higher.

The forward / backward switching mechanism 12 is provided on the power transmission path between the torque converter 11 and the CVT 13, and includes a planetary gear mechanism 12a, a forward clutch 12b, and a reverse brake 12c. When the forward clutch 12b is engaged and the reverse brake 12c is released, the rotation of the engine 3 input to the forward / backward switching mechanism 12 via the torque converter 11 is transferred from the forward / backward switching mechanism 12 to the CVT 13 while maintaining the rotation direction. It is output. On the contrary, when the forward clutch 12b is released and the reverse brake 12c is engaged, the rotation of the engine 3 input to the forward / backward switching mechanism 12 via the torque converter 11 is decelerated and the rotation direction is reversed to switch forward / backward. It is output from the mechanism 12 to the CVT 13. The flood control required by the forward / backward switching mechanism 12 is generated by a hydraulic circuit (not shown) using the flood pressure generated by the mechanical oil pump 9 or the electric oil pump 10 as the original pressure.

The CVT 13 is arranged on the power transmission path between the forward / backward switching mechanism 12 and the differential mechanism 14, and changes the gear ratio steplessly according to the vehicle speed, the accelerator opening degree which is the operation amount of the accelerator pedal, and the like. The CVT 13 includes a primary pulley 13a, a secondary pulley 13b, and a belt 13c wound around both pulleys. The CVT 13 can change the gear ratio steplessly by changing the groove widths of the primary pulley 13a and the secondary pulley 13b by flood control and changing the contact radius between the pulleys 13a and 13b and the belt 13c. The flood pressure required by the CVT 13 is generated by a hydraulic circuit (not shown) using the flood pressure generated by the mechanical oil pump 9 or the electric oil pump 10 as the original pressure.

The MG4 is a synchronous rotary electric machine in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator. The MG4 is of the primary pulley 13a via a chain 21 wound between a sprocket 31 as a first sprocket provided on the shaft of the primary pulley 13a and a sprocket 32 as a second sprocket provided on the shaft of the MG4. Connected to the shaft.

The MG 4 is branched and connected to the power transmission path connecting the engine 3 and the drive wheels 18 on the engine 3 side of the secondary pulley 13b. Further, the MG 4 is branched and connected to the power transmission path on the drive wheel 18 side of the forward / backward switching mechanism 12 including the clutch provided between the engine 3 and the primary pulley 13a of the power transmission path. Connecting the belt 13c to the shaft of the primary pulley 13a from the side opposite to the engine 3 with the belt 13c in between is included in the branch connection to the power transmission path.

The MG 4 is controlled by applying a three-phase alternating current generated by the inverter 8 based on a command from the controller 20. The MG 4 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2. Further, the MG 4 functions as a generator that generates electromotive force at both ends of the stator coil when the rotor receives rotational energy from the engine 3 and the drive wheels 18, and can charge the high voltage battery 2.

The sprocket 32 provided on the shaft of the MG4 and the sprocket 31 provided on the shaft of the primary pulley 13a are configured so that the latter has a large number of teeth (for example, the number of teeth = 1: 3), and the output rotation of the MG3. Decelerates and is transmitted to the primary pulley 13a. As a result, the torque required for the MG4 is reduced, the MG4 is miniaturized, and the degree of freedom in arranging the MG4 is improved.

The SM5 is a DC motor, and is arranged so that the pinion gear 5a can be meshed with the outer peripheral gear 3b of the flywheel 3a of the engine 3. When the engine 3 is started from a cold state for the first time (hereinafter referred to as "first start"), electric power is supplied from the low voltage battery 1 to the SM5, the pinion gear 5a is meshed with the outer gear 3b, the flywheel 3a, and further. The crankshaft is rotated. Since the low-voltage battery 1 is a lead-acid battery, the SM5 is used when the engine 3 is started for the first time, so that power can be stably supplied from the low-voltage battery 1 to the SM5 even at extremely low temperatures. This is because the SM5 can generate the torque and output required to start the engine 3 for the first time.

The torque and output required to start the engine 3 are the largest at the first start, and are smaller at the start from the warm-up state, that is, at the restart than at the first start. This is because the temperature of the engine oil is low and the viscosity of the engine oil is high at the first start, whereas the temperature of the engine oil rises and the viscosity of the engine oil decreases after the first start.

The SG6 is a synchronous rotary electric machine, which is connected to the crankshaft of the engine 3 via a V-belt 22 and functions as a generator when receiving rotational energy from the engine 3. The electric power generated in this way is charged to the high voltage battery 2 through the inverter 8. Further, the SG 6 operates as an electric motor that is rotationally driven by receiving electric power supplied from the high-voltage battery 2, and assists the driving force of the engine 3. Further, the SG6 is used to rotationally drive the crankshaft of the engine 3 to restart the engine 3 when the engine 3 is restarted from the idling stop state.

The mechanical oil pump 9 is an oil pump that operates by transmitting the rotation of the engine 3 via the chain 23. The mechanical oil pump 9 sucks up hydraulic oil stored in an oil pan (not shown) and supplies the oil to the lockup clutch 11a, the forward / backward switching mechanism 12, and the CVT 13 via a hydraulic circuit (not shown).

The electric oil pump 10 is an oil pump operated by electric power supplied from the high voltage battery 2. The electric oil pump 10 operates when the engine 3 is stopped and the mechanical oil pump 9 cannot be driven by the engine 3, such as in the EV mode or the idling stop state. Like the mechanical oil pump 9, the electric oil pump 10 sucks up the hydraulic oil stored in the oil pan and supplies the oil to the lockup clutch 11a, the forward / backward switching mechanism 12, and the CVT 13 via a hydraulic circuit (not shown). .. In particular, by securing the necessary flood pressure in the CVT 13, the slip of the belt 13c is suppressed.

The controller 20 is composed of a single or a plurality of microcomputers including a central arithmetic unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller 20 corresponds to the control unit, and by executing the program stored in the ROM or RAM by the CPU, the engine 3, the inverter 8 (MG4, SG6, the electric oil pump 10), the DC-DC converter 7, the SM5, The lockup clutch 11a, the forward / backward switching mechanism 12, the CVT 13, and the like are controlled in an integrated manner.

As the operation mode of the vehicle 100, the controller 20 drives the MG4 with the electric power supplied from the high-voltage battery 2 and travels by the driving force of the MG4 only, and the engine traveling mode of traveling by the driving force of the engine 3 only. And the HEV mode in which the vehicle travels according to the driving force of the engine 3 and the driving force of the MG 4.

In the EV mode, the vehicle 100 travels by driving only the MG4 with the electric power from the high-voltage battery 2 in a state where the forward clutch 12b and the reverse brake 12c are released (hereinafter, this state is referred to as "EV travel"). .. The EV mode is selected when the required output of the vehicle 100 is low and the remaining capacity of the high voltage battery 2 is sufficient.

In the engine running mode, the vehicle 100 runs by driving only the engine 3 with either the forward clutch 12b or the reverse brake 12c engaged. The engine running mode is selected when the required output of the vehicle 100 is relatively high.

In the HEV mode, the vehicle 100 runs by driving the engine 3 and the MG 4 with either the forward clutch 12b or the reverse brake 12c engaged. The HEV mode is selected when the required output of the vehicle 100 is high, specifically, when the required output of the vehicle 100 cannot be supplemented only by the output of the engine 3.

The controller 20 selects a driving mode based on the accelerator opening, the pedal effort of the brake pedal, and the vehicle speed in consideration of a driving mode selection map (not shown), and drives the engines 3 and MG 4 so that the selected driving mode is realized. To control.

Next, the power transmission device 30 will be described with reference to FIGS. 2 and 3.

FIG. 2 is a diagram showing the appearance of the power transmission device 30. The vertical direction in FIG. 2 corresponds to the vertical direction, the left-right direction corresponds to the front-rear direction of the vehicle 100 (the left direction is the front direction), and the vertical direction of the paper surface is the left-right direction of the vehicle 100 (the depth direction of the paper surface is the right direction). ) Corresponds. FIG. 3 is an enlarged perspective view of the vicinity of the extension portion 53 of the chain guide 50 in the power transmission device 30.

The power transmission device 30 includes a chain 21, a sprocket 31, a sprocket 32, a case 40, and a chain guide 50. The chain 21, the sprocket 31, and the sprocket 32 form a power transmission mechanism 30a.

The chain 21 is wound around the sprocket 31 and the sprocket 32. The chain 21 transmits power between the sprocket 31 and the sprocket 32. The chain 21 is driven in the forward rotation direction and the reverse rotation direction. When the vehicle 100 moves forward, the chain 21 is driven in the forward rotation direction (counterclockwise direction in FIG. 2). On the other hand, when the vehicle 100 moves backward, the chain 21 is driven in the reverse direction (clockwise in FIG. 2).

The sprocket 31 is provided on the shaft of the primary pulley 13a (see FIG. 1), and the sprocket 32 is provided on the shaft of the MG 4 (see FIG. 1). When the MG 4 operates as an electric motor, the sprocket 32 constitutes a drive-side sprocket, and the sprocket 31 constitutes a driven-side sprocket. When the MG 4 functions as a generator, the sprocket 31 constitutes a drive-side sprocket, and the sprocket 32 constitutes a driven-side sprocket. That is, when one of the sprocket 31 and the sprocket 32 constitutes the driving side sprocket, the other constitutes the driven side sprocket.

When the rotation direction is the forward rotation direction, the chain 21 and the sprocket 32 start meshing at the first meshing start portion P1. When the rotation direction is the reverse direction, the chain 21 and the sprocket 32 start meshing at the second meshing start portion P2. The first meshing start portion P1 at the time of normal rotation is located above the second meshing start portion P2 at the time of reverse rotation.

When the rotation direction is the forward rotation direction, the chain 21 and the sprocket 31 start meshing at the third meshing start portion P3 and end meshing at the fourth meshing start portion P4. When the rotation direction is the reverse direction, the chain 21 and the sprocket 31 start meshing at the fourth meshing start portion P4 and end meshing at the third meshing start portion P3.

The case 40 is a case member of the power transmission device 30. The case 40 forms an oil bath 41 in which lubricating oil is stored. The case 40 has an oil supply hole 42 as a supply hole and an oil discharge hole 43 as a discharge hole.

The oil supply hole 42 supplies the lubricating oil from the mechanical oil pump 9 or the electric oil pump 10 to the chain 21 and the sprocket 32. The oil supply hole 42 supplies oil to the first meshing start portion P1 which is the meshing start portion formed above the first meshing start portion P1 and the second meshing start portion P2. The oil supply hole 42 is provided so as to open in the inner portion of the chain 21 in the case 40.

The oil discharge hole 43 is formed on the wall surface 40a of the case 40. The oil discharge hole 43 discharges the lubricating oil to the outside when the oil level height of the lubricating oil in the oil bath 41 exceeds the set height. Specifically, when the height of the oil level O reaches the oil discharge hole 43, the lubricating oil is discharged to the outside (for example, an oil pan). That is, the height of the oil level O is maintained at the same height as the lower end of the oil discharge hole 43.

The chain guide 50 is provided in the case 40. The chain guide 50 has a guide portion 51 and extension portions 53 and 54. The chain guide 50 is provided between the sprockets 31 and 32 at a position where it is in sliding contact with the outer peripheral surface of the chain 21. In FIG. 2, the chain guide 50 is provided at a position where the chain guide 50 is in sliding contact with the outer peripheral surface of the upper chain 21 of the chains 21 hanging between the sprockets 31 and 32.

The guide portion 51 slides into contact with the outer peripheral surface of the chain 21 to guide the chain 21 in the rotational direction while suppressing vibration of the chain 21 when the power transmission mechanism 30a is driven. Further, the guide portion 51 urges the chain 21 by sliding contact with the outer peripheral surface of the chain 21, and suppresses loosening of the chain 21. The guide portion 51 has an oil dropping surface 52 as a first oil dropping surface at an end portion on the sprocket 31 side.

As shown in FIG. 3, the oil dropping surface 52 has a surface portion 52a, a sliding contact portion 52b, and continuous portions 52c and 52d. The surface portion 52a is a surface that is inclined so as to gradually approach the outer peripheral surface of the chain 21 from the outer peripheral side of the chain 21 toward the traveling direction when the chain 21 rotates in the normal direction. The width of the surface portion 52a is provided so as to be wider than the width of the chain 21. In the present embodiment, the width of the surface portion 52a is a width that covers the entire internal space of the case 40. That is, the surface portion 52a is in contact with the side surface of the internal space of the case 40.

By arranging the surface portion 52a on the outer peripheral side of the chain 21, the lubricating oil scattered from the outer periphery of the chain 21 can be collected. In particular, it is possible to collect the lubricating oil scattered from the vicinity of the fourth meshing start portion P4 where the meshing of the chain 21 and the sprocket 31 ends when the chain 21 rotates in the forward direction.

Further, the surface portion 52a has a width wider than the width of the chain 21 and gradually approaches the outer peripheral surface of the chain 21 from the outer peripheral side of the chain 21 in the traveling direction when the chain 21 rotates in the forward direction. By inclining, the collected lubricating oil can be moved along the surface portion 52a and returned to the oil bath 41. Further, since the surface portion 52a has a width that fills the internal space of the case 40, the lubricating oil flowing along the side surface of the case 40 can also be collected and returned to the oil bath 41.

That is, the surface portion 52a (oil dropping surface 52) collects the lubricating oil that is scraped up from the outer periphery of the chain 21 and scattered on the outer peripheral side of the chain 21 and returns it to the oil bath 41, thereby returning the oil level of the oil bath 41. The change (decrease) in the height of O can be suppressed.

If the surface portion 52a is inclined so as to gradually approach the outer peripheral surface of the chain 21 from the outer peripheral side of the chain 21 toward the traveling direction when the chain 21 rotates in the normal direction, the inclination angle can be appropriately set. is there. For example, based on the structure of the power transmission device 30 and the rotation speed setting of the power transmission mechanism 30a, the scattering range and the scattering angle of the lubricating oil according to the rotation speed of the power transmission mechanism 30a are predicted, and the scattering lubricating oil is determined. The angle at which the surface portion 52a can be collected to the maximum extent and can be returned to the oil bath 41 is set as the angle of the surface portion 52a.

As shown in FIG. 3, the side of the surface portion 52a on the chain 21 side has a sliding contact portion 52b that is in sliding contact with the chain 21 and continuous portions 52c and 52d that are continuous with the oil dropping surfaces 53a and 54a. The continuous portions 52c and 52d are virtually provided for the explanation of the present embodiment.

By sliding contact with the chain 21, the sliding contact portion 52b suppresses the vibration of the chain 21 when the power transmission mechanism 30a is driven, and suppresses the passage of lubricating oil between the chain 21 and the oil drop surface 52. can do.

On the sprocket 31 side of the guide portion 51, extending portions 53 and 54 that extend from the outer peripheral direction of the chain 21 toward the inner peripheral direction of the chain 21 and cover the chain 21 in the width direction are provided.

The extending portions 53 and 54 extend from the outer peripheral side of the chain 21 toward the inner peripheral side of the chain 21. The extending portions 53 and 54 have oil dropping surfaces 53a and 54a as a second oil dropping surface formed continuously from the oil dropping surface 52.

The oil dropping surfaces 53a and 54a are surfaces continuous from the continuous portions 52c and 52d of the oil dropping surface 52. The oil dropping surfaces 53a and 54a are bent along the outer circumference of the sprocket 31. Further, the oil dropping surfaces 53a and 54a are provided so as to sandwich the chain 21.

By providing the oil dropping surfaces 53a and 54a so as to sandwich the chain 21, the lubricating oil scattered from the side surface and inner circumference of the chain 21 and the sprocket 31 can be collected. The oil dropping surfaces 53a and 54a can guide the collected lubricating oil to the oil bath 41 and return it to the oil bath 41. By bending the oil dropping surfaces 53a and 54a along the outer circumference of the sprocket 31, the collected lubricating oil is guided to the oil bath 41, and the efficiency of returning the collected lubricating oil to the oil bath 41 is improved.

Further, since the oil dropping surfaces 53a and 54a are continuous from the oil dropping surface 52, the lubricating oil collected by the oil dropping surface 52 can be guided to the oil bath 41 and returned to the oil bath 41.

That is, the oil dropping surfaces 53a and 54a can collect the scattered lubricating oil and return it to the oil bath 41, and the lubricating oil collected by the oil dropping surface 52 can also be returned to the oil bath 41. As a result, the change (decrease) in the height of the oil level O of the oil bath 41 can be suppressed.

The extending portions 53 and 54 may be configured to be in sliding contact with the side surface of the chain 21. According to this configuration, it is possible to suppress the vibration of the chain 21 when the power transmission mechanism 30a is driven, and to prevent the lubricating oil from passing between the chain 21 and the extending portions 53 and 54.

Here, when there is no chain guide 50 having the oil dropping surfaces 52, 53a, 54a, the lubricating oil of the oil bath 41 is scraped up by the chain 21 when the power transmission mechanism 30a rotates at high speed, so that the lubricating oil is released. It adheres to the wall surface 40a. As a result, the height of the oil level O of the oil bath 41 is lowered. When the height of the oil level O decreases, the height of the oil level O becomes less than the set height of the oil discharge hole 43, and the lubricating oil of the oil bath 41 is not discharged from the oil discharge hole 43.

After that, when the rotation speed of the power transmission mechanism 30a changes from high-speed rotation to low-speed rotation, the amount of the lubricating oil scraped up by the chain 21 decreases. Here, when the lubricating oil adhering to the wall surface 40a returns to the oil bath 41, the total amount of the lubricating oil in the oil bath 41 may increase and the height of the oil level O may rise. As the amount of lubricating oil in the oil bath 41 increases, the amount of air that can be contained in the oil bath 41 increases relatively. As a result, when the lubricating oil of the oil bath 41 is agitated by the rotating chain 21, the air content of the lubricating oil increases. If the air content of the lubricating oil increases, the pump pressure in the mechanical oil pump 9 and the electric oil pump 10 may decrease, the pulley 13a (13b) pressure may decrease, and the like.

On the other hand, in the present embodiment, by having the chain guide 50 having the oil dropping surfaces 52, 53a, 54a, the lubricating oil scattered from the chain 21 can be collected and returned to the oil bath 41. As a result, the change in the height of the oil level O of the oil bath 41 is suppressed, and the scattered lubricating oil is suppressed from adhering to the inside of the case. This suppresses an increase in the total amount of lubricating oil in the case 40. As a result, it is possible to suppress an increase in the height of the oil level O and suppress an increase in the air content of the lubricating oil.

According to the above embodiment, the following effects are exhibited.

The power transmission device 30 is a chain 21 wound between the case 40 forming the oil bath 41 in which the lubricating oil is stored, the sprocket 31 in which at least a part is immersed in the lubricating oil in the oil bath, and the sprocket 31. A power transmission mechanism 30a having a sprocket 32 for transmitting power to and from the sprocket 31 and a chain guide 50 that is in sliding contact with the outer peripheral surface of the chain 21 are provided. It has an oil dropping surface 52 that gradually inclines from the outer peripheral side of the chain 21 toward the outer peripheral surface of the chain 21 in the traveling direction of the chain 21.

According to this configuration, the oil dropping surface 52 collects the lubricating oil scattered from the outer periphery of the chain 21 and the lubricating oil flowing along the side surface of the case 40, and moves them along the surface portion 52a to move the oil bath 41. Can be returned to. Therefore, by returning the lubricating oil scattered from the outer periphery of the chain 21 to the oil bath 41, as a result, the scattering of the lubricating oil from the outer periphery of the chain 21 is sufficiently suppressed, and the height of the oil level O of the oil bath 41 is increased. The change can be suppressed (effect corresponding to claim 1).

Further, according to this configuration, by suppressing the lubricating oil from adhering to the inside of the case 40, it is possible to suppress an increase in the total amount of the lubricating oil in the case 40. As a result, it is possible to suppress an increase in the height of the oil level O and suppress an increase in the air content of the lubricating oil (effect corresponding to claim 1).

Further, the chain guide 50 has extending portions 53 and 54 extending from the outer peripheral direction of the chain 21 toward the inner peripheral direction of the chain 21, and the extending portions 53 and 54 are continuous from the oil dropping surface 52. It has oil drop surfaces 53a and 54a that guide the lubricating oil to the oil bath 41.

According to this configuration, the oil dropping surfaces 53a and 54a can collect the scattered lubricating oil and return it to the oil bath 41, and the lubricating oil collected on the oil dropping surface 52 can also be returned to the oil bath 41. it can. As a result, the change in the height of the oil level O of the oil bath 41 can be further suppressed (the effect corresponding to claim 2).

Further, the oil dropping surfaces 53a and 54a are bent along the outer circumference of the sprocket 31.

According to this configuration, the efficiency of guiding the collected lubricating oil to the oil bath 41 and returning it to the oil bath 41 is improved. As a result, the change in the height of the oil level O of the oil bath 41 can be further suppressed (the effect corresponding to claim 3).

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configurations of the above embodiments. Absent.

For example, as shown in FIG. 4, a chain guide 60 may be provided in addition to the chain guide 50. The vertical direction in FIG. 4 corresponds to the vertical direction, the left-right direction corresponds to the front-rear direction of the vehicle 100 (the left direction is the front direction), and the vertical direction of the paper surface is the left-right direction of the vehicle 100 (the depth direction of the paper surface is the right direction). ) Corresponds. In FIG. 4, the chain guide 60 is provided at a position where the chain guide 60 is in sliding contact with the outer peripheral surface of the lower chain 21 of the chains 21 hanging between the sprockets 31 and 32. Here, the oil dropping surface 62 of the chain guide 60 is configured to gradually incline from the outer peripheral side of the chain 21 toward the outer peripheral surface of the chain 21 in the traveling direction when the chain 21 rotates in the reverse direction. Since the configuration of the chain guide 60 other than the oil dropping surface 62 is the same as that of the chain guide 50, the description thereof will be omitted.

According to this configuration, the lubricating oil scattered from the chain 21 and the sprocket 31 when the power transmission mechanism 30a rotates in the reverse direction can be collected and returned to the oil bath 41.

Further, in the configuration having the chain guides 50 and 60, the extension portion 53 of the chain guide 50 and the extension portion 63 of the chain guide 60 are connected, and the extension portion 54 of the chain guide 50 and the extension portion of the chain guide 60 are connected. A configuration in which 64 is connected may be used. According to this configuration, the area for collecting the lubricating oil is expanded, and the collecting performance of the scattered lubricating oil can be improved. In addition, the efficiency of returning the collected lubricating oil to the oil bath 41 is improved.

100 Vehicle 21 Chain 30 Power transmission device 31 Sprocket (1st sprocket)
32 sprocket (second sprocket)
40 Case 50 Chain guide 52 Oil drop surface (first oil drop surface)

Claims (3)

It is a power transmission device
A case that forms an oil bath in which lubricating oil is stored, and
A first sprocket in which at least a part is immersed in the lubricating oil in the oil bath, and a second sprocket in which power is transmitted between the first sprocket by a chain wound between the first sprocket and the first sprocket. With a power transmission mechanism that has,
A chain guide that is in sliding contact with the outer peripheral surface of the chain,
With
The chain guide has a first oil dropping surface that gradually inclines from the outer peripheral side of the chain toward the outer peripheral surface of the chain in the traveling direction of the chain.
A power transmission device characterized by that. The power transmission device according to claim 1.
The chain guide has an extending portion extending from the outer peripheral side of the chain toward the inner peripheral side of the chain.
The extending portion has a second oil dropping surface that is continuously formed from the first oil dropping surface and guides the lubricating oil to the oil bath.
A power transmission device characterized by that. The power transmission device according to claim 2.
The second oil drop surface bends along the outer circumference of the first sprocket.
A power transmission device characterized by that.

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