Hybrid vehicle drive unit

Abstract

To provide a hybrid vehicle drive unit that is able to reduce, by means of a small member, the possibility that large vertical bending vibration is generated in the hybrid vehicle drive unit due to a device vibrating at a frequency lower than a resonance frequency peculiar to the hybrid vehicle drive unit.SOLUTION: A hybrid vehicle drive unit includes a metal stiffener 65 connected to a second case 50 or a second connection portion 37 and to a cylinder block 20, a cylinder head 25 or a first connection portion 32.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hybrid vehicle drive unit. [Background technology]

[0002] BACKGROUND ART A hybrid vehicle drive unit is known that includes an engine, an electric motor, a gear mechanism that operates by receiving driving force from the engine and the electric motor, and a PCU (Power Control Unit) that controls the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-195786 Summary of the Invention [Problem to be solved by the invention]

[0004] If the resonant frequency of the vertical bending vibration of the hybrid vehicle drive unit matches the vibration generated in the components of the hybrid vehicle drive unit, there is a risk that large vertical bending vibration will occur in the hybrid vehicle drive unit.

[0005] Taking the above facts into consideration, the present invention aims to provide a hybrid vehicle drive unit that can reduce, by using small components, the risk of large vertical bending vibrations occurring in the hybrid vehicle drive unit due to devices that vibrate at a frequency lower than the hybrid vehicle drive unit's inherent resonant frequency. [Means for solving the problem]

[0006] The hybrid vehicle drive unit of claim 1 is a hybrid vehicle drive unit comprising: a first case that houses a gear mechanism and an electric motor that can apply driving force to the gear mechanism; an engine that can apply driving force to the gear mechanism; and a second case that is connected to the first case so as to be positioned above the first case, horizontally faces a part of the engine, and houses a control device that can control the electric motor, wherein the first case has a first connection portion that is connected to a portion of the engine that is positioned below the part of the engine, and a second connection portion that is positioned above the first connection portion, horizontally faces the engine, and is connected to the second case, and is provided with a metal stiffener that is connected to the second case or the second connection portion and the engine or the first connection portion.

[0007] In the specification and claims, "two members (parts) are connected (fixed) together" means both a direct connection (fixing) of the two members (parts) together and an indirect connection (fixing) of the two members (parts) together by interposing another member between them. Therefore, for example, claim 1 also includes a case where the first connecting part of the first case is connected to the lower part of the engine via a member other than the first connecting part and the engine.

[0008] The hybrid vehicle drive unit of claim 1 includes a first case housing a gear mechanism and an electric motor capable of applying driving force to the gear mechanism, an engine capable of applying driving force to the gear mechanism, and a second case connected to the first case so as to be positioned above the first case, horizontally facing a portion of the engine, and housing a control device capable of controlling the electric motor. The first case includes a first connection portion connected to a portion of the engine positioned below the portion, and a second connection portion connected to the second case, positioned above the first connection portion, horizontally facing the engine. Therefore, for example, when the electric motor or the engine operates, the second case housing the control device vibrates, and the vibration of the second case causes the second connection portion of the first case to vibrate. Furthermore, the vibration of the second connection portion causes vertical bending vibrations in the hybrid vehicle drive unit.

[0009] However, the hybrid vehicle drive unit of claim 1 includes a metal stiffener connected to the second case or second connection portion and the engine or first connection portion. In this case, connecting the stiffener to the second case or second connection portion and the engine or first connection portion increases the rigidity of the hybrid vehicle drive unit compared to when they are not connected. In other words, connecting the stiffener to the second case or second connection portion and the engine or first connection portion increases the resonant frequency of the vertical bending vibration of the hybrid vehicle drive unit compared to when they are not connected. Therefore, the hybrid vehicle drive unit of claim 1 uses the stiffener to reduce the risk of large vertical bending vibration occurring in the hybrid vehicle drive unit due to devices that vibrate at a frequency lower than the resonant frequency specific to the hybrid vehicle drive unit.

[0010] Furthermore, the stiffener is provided in a space surrounded by the part of the engine, the second case, the first connecting portion, and the second connecting portion. Therefore, the stiffener is unlikely to be large. In other words, the stiffener of the hybrid vehicle drive unit of claim 1 can be constructed using small members.

[0011] The hybrid vehicle drive unit of claim 2 is the same as claim 1, except that a first flange made of metal is provided on the engine, a second flange is provided at the first connection portion of the first case, which is also made of metal, and is fixed to the first flange, and the stiffener is fixed to the first connection portion.

[0012] In the hybrid vehicle drive unit of claim 2, a metal first flange is provided on the engine, and a metal first case has a first connection portion on which a second flange is fixed. This allows the engine and the first case (first connection portion) to be firmly fixed together. In other words, the engine and the first connection portion can be considered as a single rigid body. Furthermore, a stiffener is fixed to the first connection portion. Therefore, in the hybrid vehicle drive unit of claim 2, the stiffener suppresses engine vibration, thereby improving the bending rigidity of the hybrid vehicle drive unit.

[0013] The hybrid vehicle drive unit described in claim 3 is the same as claim 2, in that a through hole is formed in the upper surface of the first connection portion, which is a hollow body, and a through hole is formed in the stiffener, positioned directly above the through hole.

[0014] In the hybrid vehicle drive unit of claim 3, the through hole formed in the upper surface of the hollow first connection portion can be exposed by utilizing the through hole provided in the stiffener. Furthermore, the stiffness of the stiffener is lower than when no through hole is formed. In other words, the resonant frequency of the hybrid vehicle drive unit is lower than when a stiffener without a through hole is fixed to the hybrid vehicle drive unit. Therefore, the resonant frequency of the hybrid vehicle drive unit can be prevented from becoming excessively high.

[0015] The hybrid vehicle drive unit described in claim 4 is the same as claim 2 or 3, and includes a first portion connected to the first connection portion and a second portion connected to the second connection portion.

[0016] The stiffener of the hybrid vehicle drive unit of claim 4 has a first portion connected to the first connection portion and a second portion connected to the second connection portion. That is, this stiffener is substantially L-shaped. Therefore, in the hybrid vehicle drive unit of claim 4, the stiffener can be constructed using small members. [Effects of the Invention]

[0017] As described above, the hybrid vehicle drive unit of the present invention has the excellent effect of being able to reduce, by using small components, the risk of large vertical bending vibrations occurring in the hybrid vehicle drive unit due to devices that vibrate at a frequency lower than the hybrid vehicle drive unit's inherent resonant frequency. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a schematic front view of a hybrid vehicle drive unit according to an embodiment. [Figure 2] FIG. 2 is a schematic plan view of a hybrid vehicle drive unit. [Figure 3] 1 is a front view of a hybrid vehicle drive unit in a separated state, showing a first component, a second component, a first cover member, a second case, a second cover member, and a stiffener. FIG. [Figure 4] FIG. 2 is an exploded perspective view of a first component, a second component, a second case, and a stiffener. [Figure 5] FIG. 2 is a perspective view of a first component, a second component, and a second case joined together. [Figure 6] FIG. 2 is a perspective view of a first component, a second component, a second case, and a stiffener joined together. [Figure 7] FIG. 2 is a schematic plan view of a first component, a second component, a stiffener, and a bolt. [Figure 8] 10 is a schematic front view of a hybrid vehicle drive unit when vertical bending vibration occurs; FIG. [Figure 9] FIG. 10 is a schematic front view of a hybrid vehicle drive unit according to a first modified example. [Figure 10] FIG. 10 is a schematic front view of a hybrid vehicle drive unit according to a second modified example. [Figure 11] FIG. 10 is a schematic front view of a hybrid vehicle drive unit according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of a hybrid vehicle drive unit 10 (hereinafter simply referred to as unit 10) according to the present invention will be described with reference to the accompanying drawings. In the drawings, an arrow FR indicates the front side in the longitudinal direction of the vehicle, an arrow LH indicates the left side in the lateral direction of the vehicle, and an arrow UP indicates the upper side in the vertical direction of the vehicle.

[0020] 1, the unit 10 is installed in the engine compartment of a vehicle. The unit 10 includes an engine 15, a first case 30, a first cover member 40, an electric motor 42, a gear mechanism 44, a second case 50, a PCU (Power Control Unit) (control device) 52, a second cover member 55, and a stiffener 65.

[0021] The engine 15 includes an oil pan 17, a cylinder block 20, and a cylinder head 25. The metal cylinder block 20 is fixed to the top of the metal oil pan 17, which forms the lower end of the engine 15. The cylinder block 20 includes a block main body 21 and a first flange 22 fixed to the left side of the block main body 21 and having an annular side surface. Inside the block main body 21, for example, are provided a piston that can move up and down, a rotatable crankshaft, and a connecting rod that links the piston and crankshaft (all of which are not shown). An opening (not shown) is provided on the left side of the block main body 21. When the cylinder block 20 is viewed from the left side, this opening is located on the inner circumferential side of the first flange 22.

[0022] The lower surface of a metal cylinder head 25 is fixed to the upper surface of the block body 21. A recess (not shown) is formed in the lower part of the cylinder head 25, and this recess, together with the internal space of the block body 21 and the upper end surface of the piston, forms a combustion chamber. Furthermore, the cylinder head 25 is formed with an intake port and an exhaust port (not shown) that communicate with the combustion chamber. Furthermore, a camshaft (not shown) is provided inside the cylinder head 25.

[0023] The first case 30 has a first component part 31 and a second component part 36, both of which are cast products made of metal (for example, aluminum).

[0024] The first component part 31 has a first connecting part 32 and a second flange 33. The first connecting part 32 is a hollow member with both left and right side surfaces open, and an annular second flange 33 is fixed to the right end part of the first connecting part 32. The first connecting part 32 and the second flange 33 are integrally manufactured by casting. The side surface shape of the second flange 33 is substantially the same as that of the first flange 22. Furthermore, as shown in FIG. 4, a pair of front and rear bolt holes 34, which are female-threaded holes, are formed in the upper wall part of the first connecting part 32. Furthermore, as shown in FIG. 7, a circular through hole 35 is formed in the upper wall part of the first connecting part 32. The through hole 35 can be detachably covered with a lid 39 (see FIG. 4).

[0025] The second component 36 is a hollow box-shaped member whose front shape is larger than that of the first component 31. Openings smaller than these left and right side surfaces are formed on both left and right side surfaces of the second component 36. As shown in FIGS. 1 and 5, the left side surface of the first connection portion 32 is fixed to the right side surface of the second component 36, and the opening on the right side surface of the first connection portion 32 communicates with the opening on the left side surface of the second component 36. The opening on the left side surface of the second component 36 is detachably closed by a first cover member 40, which is a metal (e.g., aluminum) casting. An opening smaller than this upper wall portion is formed in the upper wall portion of the second component 36.

[0026] The portion of the second component 36 located above the first connecting portion 32 is made up of a second connecting portion 37. Furthermore, as shown in Figure 4, a pair of front and rear bolt holes 38, which are female-threaded holes, are formed in the right wall portion of the second connecting portion 37.

[0027] 1, the right side of the second flange 33 of the first connecting portion 32 and the left side of the first flange 22 of the cylinder block 20 (a portion located below a part of the engine 15) are in contact with each other. Furthermore, the first flange 22 and the second flange 33 are firmly fixed to each other using a plurality of metal bolts (not shown). Therefore, the cylinder block 20 and the first component portion 31 can be considered as a single rigid body.

[0028] As shown in FIG. 1 , an electric motor 42 is provided inside the second component 36, and a gear mechanism 44 is provided inside the first connection portion 32 and the second component 36. The electric motor 42 is fixed to the second component 36. The gear mechanism 44 is linked to the electric motor 42. The gear mechanism 44 is further linked to the crankshaft via a linking member provided inside the cylinder block 20 and the first connection portion 32. The gear mechanism 44 is further connected to the drive wheels of the vehicle via a linking mechanism (not shown) including an axle. A harness (not shown) connected to the electric motor 42 passes upward through the opening provided in the upper wall of the second component 36.

[0029] The first case 30 and the members (devices) housed in the first case 30 are components of a transaxle 46.

[0030] The lower surface of the second case 50, which is a metal (e.g., aluminum) casting, is fixed to the upper surface of the second component 36. The second case 50 is a hollow box-shaped member that faces the cylinder head 25 (part of the engine 15) in the left-right direction (horizontal direction). The upper and lower wall portions of the second case 50 are formed with openings that are smaller than the upper and lower wall portions. As shown in FIG. 1, a PCU 52 is provided inside the second case 50 and is fixed to the second case 50. Furthermore, the harness is connected to the PCU inside the second case 50. The PCU has the function of controlling the electric motor 42.

[0031] The opening in the upper wall of the second case 50 is detachably closed by a second cover member 55, which is a metal (for example, aluminum) casting.

[0032] As shown in FIG. 2, if the value obtained by dividing the left-right dimension by the front-rear dimension of the second component 36, the second case 50, and the second cover member 55 (the second component 36 and the second case 50 are not shown in FIG. 2) is defined as a first ratio, and the value obtained by dividing the left-right dimension by the front-rear dimension of the engine 15 is defined as a second ratio, the first ratio is smaller than the second ratio. Furthermore, the second case 50 is supported by a portion of a body frame member provided on the left side of the engine compartment of the vehicle, and the upper part of the engine 15 is supported by a portion of a body frame member provided on the right side of the engine compartment. In other words, the unit 10 is provided in the engine compartment while being suspended by the left and right body frame members. Furthermore, as shown in FIG. 1, a stiffener installation space 62 is formed between the upper surface of the first connecting portion 32, the left side surfaces of the block main body 21 and the cylinder head 25, and the right side surface of the second connecting portion 37 and the second case 50.

[0033] 1, 4, 6, and 7, the metal (for example, cast iron) stiffener 65 is an integrally molded product having a first portion 66 and a second portion 68. The first portion 66 is a plate-shaped portion that is approximately perpendicular to the up-down direction, and the second portion 68 is a plate-shaped portion that is approximately perpendicular to the left-right direction, and its lower end is connected to the left end of the first portion 66. In other words, the first portion 66 and the second portion 68 are approximately perpendicular to each other. In other words, the front shape of the stiffener 65 is approximately L-shaped.

[0034] A notch 70 is formed in the right edge of the first portion 66. Furthermore, a groove 72 extending in a direction substantially parallel to the front-to-rear direction and open at both ends is formed in the upper surface of the front part of the first portion 66. Furthermore, a through-hole 74 having a substantially circular cross section is formed in the first portion 66 and the second portion 68, penetrating the first portion 66 in the up-down direction while recessing the right side surface of the second portion 68. Furthermore, a pair of front and rear bolt holes 76 are formed in the first portion 66, and a pair of front and rear bolt holes 78 are formed in the second portion 68.

[0035] 1, 6, and 7, the first portion 66 is placed on the upper surface of the first connecting portion 32, a pair of bolts 80 passing through each bolt hole 76 is threaded into each bolt hole 34, and a head 81 of each bolt 80 is pressed against the upper surface of the first portion 66. The left side of the second portion 68 is in contact with the right side of the second connecting portion 37, a pair of bolts 84 passing through each bolt hole 78 is threaded into each bolt hole 38, and a head 85 of each bolt 84 is pressed against the right side of the second portion 68. In this manner, the stiffener 65 is fixed to the first connecting portion 32 and the second connecting portion 37 using the bolts 80, 84. Therefore, the rigidity of the unit 10 including the first connecting portion 32 and the second connecting portion 37 is greater than if the unit 10 did not include the stiffener 65.

[0036] (Action and effect) Next, the operation and effects of this embodiment will be described.

[0037] As described above, the unit 10 includes the first case 30 that houses the gear mechanism 44 and the electric motor 42 that can apply driving force to the gear mechanism 44, the cylinder block 20 that houses the crankshaft and other components that can apply driving force to the gear mechanism 44, the engine 15 that has the cylinder head 25 connected to the upper part of the cylinder block 20 and the oil pan 17 connected to the lower part of the cylinder block 20, and the second case 50 that is connected to the second connection part 37 of the first case 30, is located above the second connection part 37, faces the cylinder head 25 in the horizontal direction, and houses the PCU 52. The first case 30 further includes the first connection part 32 that is connected to the second flange 33 that is fixed to the first flange 22 of the cylinder block 20, and the second connection part 37 that is located above the first connection part 32 and is connected to the second case 50. Therefore, for example, when at least one of the engine 15 and the electric motor 42 operates, the unit 10, which is suspended by left and right vehicle body frame members, vibrates. At this time, the second case 50 that houses the PCU 52 vibrates significantly in the left-right direction, and the vibration of the second case 50 causes the second connection part 37 to buckle and pull, which in turn vibrates the second connection part 37. At this time, the engine 15 also vibrates in the left-right direction, but because the first ratio is smaller than the second ratio as described above, the second case 50 vibrates more significantly in the left-right direction than the engine 15. Furthermore, the vibration of the second connection part 37 causes bending vibration in the up-down direction in the unit 10, as shown in FIG.

[0038] However, in the unit 10 of this embodiment, a metal stiffener 65 is connected to the second connection portion 37 and the first connection portion 32. Therefore, when bending vibration occurs in the unit 10 in the vertical direction, stress is generated in the stiffener 65. In other words, some of the stress generated in the unit 10 is not concentrated on the second connection portion 37 and the first connection portion 32. This increases the rigidity of the second connection portion 37 compared to when the stiffener 65 is not connected to the second connection portion 37. Therefore, even if the second case 50 vibrates, the second connection portion 37 is less likely to vibrate significantly. Furthermore, in this embodiment, a metal first flange 22 is provided on the cylinder block 20, a metal second flange 33 is provided on the first connection portion 32, and the first flange 22 and the second flange 33 are firmly fixed. Therefore, the cylinder block 20 and the first component 31 can be considered as a single rigid body. Furthermore, a first portion 66 of the stiffener 65 is fixed to the first connection portion 32. Therefore, the stiffener 65 suppresses vibration of the cylinder block 20 and the cylinder head 25 when at least one of the engine 15 and the electric motor 42 is operating. As a result, the resonance frequency of the vertical bending vibration of the unit 10 is higher than when the stiffener 65 is not connected to the second connection portion 37 and the first connection portion 32. In other words, the stiffener 65 increases the bending rigidity of the unit 10 against vertical bending. This reduces the risk of large vertical bending vibration occurring in the unit 10 due to devices or the like that vibrate at a frequency lower than the unit 10's inherent resonance frequency (natural frequency).

[0039] For example, the inherent resonant frequency of unit 10 when unit 10 does not include stiffener 65 and the frequency of the vibration of the crankshaft when it rotates have order components that are close in magnitude. However, because stiffener 65 is connected to second connecting portion 37 and first connecting portion 32, the resonant frequency of unit 10 in this embodiment has a value that is significantly larger than the frequency order components when the crankshaft rotates. Therefore, there is little risk that large bending vibrations in the vertical direction will occur in unit 10 due to the rotation of the crankshaft when engine 15 is operating.

[0040] Furthermore, the stiffener 65 has a generally L-shaped structure including a first portion 66 connected to the first connecting portion 32 and a second portion 68 connected to the second connecting portion 37, and is a member provided in the stiffener installation space 62 of the unit 10. In other words, the stiffener 65 is a small member. That is, in this embodiment, the risk of large vertical bending vibrations occurring in the unit 10 due to a device that vibrates at a frequency lower than the unit 10's inherent resonant frequency can be reduced by using the stiffener 65, which is a small member.

[0041] Furthermore, the stiffener 65 has cutouts 70, grooves 72, and through-holes 74 formed separately from the bolt holes 76, 78. Therefore, the stiffness of the stiffener 65 is lower than when the cutouts 70, grooves 72, and through-holes 74 are not formed. In other words, the resonant frequency of the unit 10 of this embodiment is lower than when a stiffener 65 without the cutouts 70, grooves 72, and through-holes 74 is fixed to the unit 10. If the resonant frequency of the unit 10 were set to an excessively high value (for example, about 400 Hz) and resonance occurred in the unit 10, the unit 10 could emit a sound that is unpleasant to vehicle occupants. However, in this embodiment, the stiffener 65 is provided with the cutouts 70, grooves 72, and through-holes 74 to intentionally reduce the mechanical strength of the stiffener 65, so such a problem is less likely to occur.

[0042] Furthermore, since stiffener 65 has groove 72, it is possible to place a portion of EGR cooler hose 90 routed inside the vehicle as shown in FIG. 7 in groove 72. It is also possible to place a portion of a shift cable (not shown) in groove 72.

[0043] Furthermore, the stiffener 65 has a through hole 74. As shown in Fig. 7, in a plan view, the through hole 74 is concentric with the through hole 35 of the first connecting part 32. Therefore, when the lid 39 is removed from the through hole 35, it is possible to suck out oil present in the internal space of the first connecting part 32, for example, by using a pipe (not shown) inserted into the internal space of the first connecting part 32 via the through hole 74 and the through hole 35.

[0044] The unit 10 according to the embodiment has been described above, but the design can be modified as appropriate within the scope of the present invention.

[0045] For example, the present invention may be implemented in the form of a first modified example shown in Fig. 9. One end of a metal stiffener 92 of a unit 10A of the first modified example is fixed to the block body 21, and the other end is fixed to the second connecting portion 37.

[0046] The present invention may also be embodied in a second modified embodiment shown in Fig. 10. In the second modified embodiment, a metal stiffener 94 of a unit 10B has one end fixed to the block body 21 and the other end fixed to the second case 50.

[0047] The present invention may also be embodied in a third modified embodiment shown in Fig. 11. One end of a metal stiffener 96 of a unit 10C of the third modified embodiment is fixed to the cylinder head 25, and the other end is fixed to the second case 50.

[0048] In these first to third modified examples, the risk of large vertical bending vibrations occurring in units 10A, 10B, and 10C due to devices vibrating at frequencies lower than the inherent resonant frequencies of units 10A, 10B, and 10C can be reduced by using stiffeners 92, 94, and 96, which are small components.

[0049] Furthermore, although not shown in the figures, the stiffener may have a structure different from that of the embodiment and each modified example, as long as a part of it is connected to the cylinder head 25, the block main body 21 or the first connection part 32 and another part is connected to the second connection part 37 or the second case 50.

[0050] The first component part 31 and the second component part 36 may be integrally molded. For example, the first case 30 may be a metal casting having the first component part 31 and the second component part 36. [Explanation of symbols]

[0051] 10 10A 10B 10C Hybrid vehicle drive unit (unit) 15 Engine 20 Cylinder block 22 First flange 25 cylinder head 30 Case 1 32 First connection part 33 Second flange 35 through holes 37 Second connection part 42 Electric motor 44 Gear mechanism 50 Case 2 52 PCU (control unit) 65 Stiffener 66 Part 1 68 Part 2 74 Through Hole 92 94 96 Stiffener

Claims

1. A hybrid vehicle drive unit including: a first case that houses a gear mechanism and an electric motor that can apply driving force to the gear mechanism; an engine that can apply driving force to the gear mechanism; and a second case that houses a control device that is connected to the first case so as to be located above the first case and that faces a part of the engine in a horizontal direction and that can control the electric motor, the first case has a first connection portion connected to a portion of the engine located below the part of the engine, and a second connection portion located above the first connection portion, facing the engine in the horizontal direction, and connected to the second case, A hybrid vehicle drive unit comprising a metal stiffener connected to the second case or the second connection portion and the engine or the first connection portion.

2. The engine is provided with a first flange made of metal, a second flange fixed to the first flange is provided at the first connection portion of the first case made of metal, 2. The hybrid vehicle drive unit according to claim 1, wherein the stiffener is fixed to the first connecting portion.

3. a through hole is formed in an upper surface of the first connection portion, which is a hollow body; 3. The hybrid vehicle drive unit according to claim 2, wherein the stiffener has a through hole positioned directly above the through hole.

4. The stiffener is a first portion connected to the first connection portion; a second portion connected to the second connection portion; 4. The hybrid vehicle drive unit according to claim 2 or 3, comprising:

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