Power transmission device

Abstract

A power transmission device, which is a continuously variable transmission (200), includes: a transmission (1) having a side cover (30), a housing (40), and a casing (10) clamped by the side cover (30) and the housing (40); an oil pump (180) disposed within the transmission (1); and a pair of gears (147), (163) disposed within the transmission (1). An axial rib (25) having a linear shape extending from the side cover (30) toward the housing (40) is formed on an outer wall surface at a position adjacent to the pair of gears (147), (163) within the casing (10). The axial rib (25) is disposed on a straight line extending vertically from the oil pump (180) and is partially disposed at a position for suppressing the meshing reaction force of the pair of gears (147), (163). Thereby, a rib structure designed with weight reduction in mind in the transmission can be provided.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of January 10, 2019, an application number of 201980009556.8, an invention title of "Power Transmission Device", and applicants of JATCO LTD. and NISSAN MOTOR CO., LTD.

[0002] Technical Field

[0003] The present invention relates to a power transmission device. Background Art

[0004] In Patent Document 1, a structure is disclosed in which grid-shaped ribs are provided over the entire outer wall surface of a transmission.

[0005] However, when grid-shaped ribs are provided over the entire outer wall surface, the weight of the transmission increases.

[0006] Therefore, a rib structure designed in consideration of weight reduction is required.

[0007] Prior Art Documents

[0008] Patent Documents

[0009] Patent Document 1: Japanese Patent Laid-Open No. 4-113062 Summary of the Invention

[0010] The power transmission device of the present invention includes:

[0011] a housing having a first housing member, a second housing member, and a third housing member sandwiched between the first housing member and the second housing member;

[0012] an oil pump disposed in the housing;

[0013] a pair of gears disposed in the housing,

[0014] ribs are formed on the outer wall surface of the third housing member at positions adjacent to the pair of gears, and the ribs have a linear shape extending from the first housing member to the second housing member,

[0015] the ribs are disposed on a straight line extending in the vertical direction from the oil pump, and are partially disposed at positions for suppressing the meshing reaction force of the pair of gears,

[0016] the ribs have a shape connecting both a first connection point between the first housing member and the third housing member and a second connection point between the second housing member and the third housing member,

[0017] The uppermost part of the rib is located at a position higher than the center points of the connection holes of the first connection point and the second connection point.

[0018] According to the present invention, a rib structure designed in consideration of weight reduction can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a diagram for explaining a belt-type continuously variable transmission.

[0020] Figure 2 It is a diagram for explaining a housing constituting a transmission.

[0021] Figure 3 It is a perspective view of a housing constituting a transmission as viewed from the outer housing side.

[0022] Figure 4 It is a diagram for explaining an axial rib provided on the housing.

[0023] Figure 5 It is a perspective view of an existing housing as viewed obliquely from above. DETAILED DESCRIPTION

[0024] Hereinafter, with reference to Figures 1 to 4 , an embodiment of the present invention will be described by taking the case where the power transmission device is a belt-type continuously variable transmission 200 for a vehicle as an example.

[0025] Figure 1 It is a diagram for explaining the belt-type continuously variable transmission 200.

[0026] In Figure 1 , it is a transmission path of rotational driving force transmitted via each rotational transmission shaft (first shaft, second shaft, third shaft, fourth shaft), and schematically shows the range from the torque converter 111 through the speed change mechanism 120 to the differential device 170.

[0027] Figure 2 It is a diagram for explaining the housing 10. Figure 2 (a) of Figure 2 is a view of the housing 10 as viewed from the outer housing 40 side, Figure 2 (b) of

[0028] As Figure 1 shown, the continuously variable transmission 200 is a device that steplessly changes the rotational driving force output from an engine (not shown) and transmits it to the drive wheels.

[0029] The continuously variable transmission 200 includes a torque converter 111 that inputs rotational driving force from the engine, a forward / reverse switching mechanism 112, a speed change mechanism 120, a reduction gear 161, a differential device 170, an oil pump 180, and a transmission case 1 that houses these components.

[0030] The forward / reverse switching mechanism 112 includes a planetary gear mechanism and inputs the rotational driving force output from the torque converter 111 to the speed change mechanism 120 in clockwise rotation / counterclockwise rotation.

[0031] The torque converter 111, the forward / reverse switching mechanism 112, and the primary pulley 130 of the speed change mechanism 120 rotate about an axis X1 (first axis).

[0032] The secondary pulley 140 of the speed change mechanism 120 rotates about an axis X2 (second axis). The reduction gear 161 rotates about an axis X3 (third axis). The differential device 170 rotates about an axis X4 (fourth axis).

[0033] The axis X1, the axis X2, the axis X3, and the axis X4 are arranged parallel to each other.

[0034] As Figure 2 shown in (a), in the vertical direction with respect to the installation state of the continuously variable transmission 200 as a reference, the axis X2 and the axis X3 are arranged at substantially the same height position. The axis X4 is arranged substantially vertically below the axis X3. The axis X1 is substantially at the same height as the axis X4 and is arranged obliquely below the axis X2.

[0035] As Figure 1 shown, the speed change mechanism 120 is a belt-type CVT (Continuously Variable Transmission). The speed change mechanism 120 has a primary pulley 130 on the input side, a secondary pulley 140 on the output side, and a belt 151 that winds around the primary pulley 130 and the secondary pulley 140 to transmit rotational driving force.

[0036] The primary pulley 130 has a fixed pulley 131 that does not displace axially and a movable pulley 135 that can displace axially relative to the fixed pulley 131.

[0037] The fixed pulley 131 is rotatably supported on the housing 10 via a ball bearing 191. The output rotation of the forward / reverse switching mechanism 112 is input to the fixed pulley 131.

[0038] A V-shaped groove for winding the belt 151 is formed between the pulley portion 132 of the fixed pulley 131 and the pulley portion 136 of the movable pulley 135. And, corresponding to the oil pressure, since the movable pulley 135 displaces relative to the fixed pulley 131, the groove width of the V-shaped groove changes. As a result, the winding radius of the belt 151 of the primary pulley 130 changes.

[0039] The secondary pulley 140 has a fixed pulley 141 that does not axially displace and a movable pulley 145 that can axially displace relative to the fixed pulley 141.

[0040] The housing 40 side of the fixed pulley 141 ( Figure 1 the right side of the paper surface) is rotatably supported on the housing 10 via a roller bearing 192.

[0041] A V-shaped groove for winding the belt 151 is formed between the pulley portion 142 of the fixed pulley 141 and the pulley portion 146 of the movable pulley 145. And, corresponding to the oil pressure, the movable pulley 145 displaces relative to the fixed pulley 141, and the groove width of the V-shaped groove changes. As a result, the winding radius of the belt 151 of the second pulley 140 changes.

[0042] That is, by changing the winding radius of the belt 151 of the primary pulley 130 and the winding radius of the belt 151 of the secondary pulley 140 respectively, the power is speeded up and transmitted from the primary pulley 130 to the secondary pulley 140.

[0043] The gear 147 is spline-fitted to the housing 40 side of the fixed pulley 141, and this gear 147 meshes with the gear 163 on the side of the reduction gear 161.

[0044] The reduction gear 161 constitutes a gear mechanism that transmits the rotation of the fixed pulley 141 to the differential device 170.

[0045] The side cover 30 side of the reduction gear 161 ( Figure 1 the left side of the paper surface) is rotatably supported on the housing 10 via a tapered roller bearing 19.

[0046] In the reduction gear 161, the gear 163 is spline-fitted to the housing 40 side ( Figure 1 the right side of the paper surface).

[0047] This gear 163 meshes with the gear 147 on the side of the secondary pulley 140, and the gears 147 and 163 constitute a pair of gears that participate in the transmission of the rotational driving force between the secondary pulley 140 and the reduction gear 161.

[0048] And, when the rotational driving force is transmitted, a meshing reaction force acts on the gears 147 and 163. The acting direction of this meshing reaction force is the direction in which the gears 147 and 163 are displaced in the direction away from each other (the separating direction).

[0049] In the reduction gear 161, a gear portion 164 is provided on the side cover 30 side. This gear portion 164 meshes with the final gear 162 fixed to the differential housing 171 of the differential device 170.

[0050] The differential device 170 is a device that transmits the rotational driving force transmitted via the final gear 162 to the left and right drive wheels (not shown) and enables the left and right drive wheels to rotate differentially.

[0051] The differential device 170 includes a spherical shell-shaped differential housing 171, a planetary shaft 172 fixed to the differential housing 171, a pair of planetary gears 173 that rotate about the planetary shaft 172, and a pair of side gears 174 that mesh with the planetary gears 173.

[0052] The drive shaft 310 that rotates integrally with the drive wheel is spline-fitted with the side gear 174. In Figure 1 the figure, the illustration of the drive shaft 310 on the right side in the figure is omitted.

[0053] The differential housing 171 is rotatably supported on the housing 10 via a tapered roller bearing 194.

[0054] Figure 3 is a perspective view of the housing 10 as viewed obliquely from above the outer housing 40 side.

[0055] Figure 4 is a figure for explaining the axial ribs 25 (reinforcing ribs) provided on the housing 10. Figure 4 (a) of is a perspective view showing an enlarged view of the axial rib 25 of the housing 10, Figure 4 and (b) of is a cross-sectional view of the axial rib 25 cut in plane A in (a), Figure 4 and (c) of is a cross-sectional view of the axial rib 25 cut along line B-B in (b). Figure 4 and (d) of is a cross-sectional view of the axial rib 25 cut along line C-C in (c), Figure 4 and (e) of is a cross-sectional view of the axial rib 25 cut along line D-D in (c).

[0056] In addition, in Figure 4 (c) of , the outer housing 40 and the side cover 30 assembled on the housing 10 are shown by phantom lines together with the bolts 91, 92.

[0057] As Figure 1 shown, the transmission 1 is a box body composed of three parts and includes a housing 10 (third housing component), a side cover 30 (first housing component), and an outer housing 40 (second housing component).

[0058] Specifically, the side cover 30 and the outer housing 40 clamp the housing 10 axially.

[0059] The housing 10 is generally a thin cylindrical body in the axial direction, and a speed change mechanism 120 and the like are housed therein. The housing 10 generally includes a cylindrical outer peripheral wall portion 11 that constitutes the outer contour and an intermediate wall portion 12 that extends inward from the outer peripheral wall portion 11 and is spaced apart in the axial direction. Through holes 13a, 14a, 15a, and 16a that penetrate in the axial direction are formed in the intermediate wall portion 12.

[0060] As Figure 2 shown in (a) of, the through hole 13a is formed centered on the axis X1, and a cylindrical support wall portion 13 surrounding the through hole 13a is formed on the intermediate wall portion 12.

[0061] The support wall portion 13 is externally fitted with a ball bearing 191 (refer to Figure 1 ), and is the part that supports the ball bearing 191.

[0062] The through hole 14a is formed centered on the axis X2, and a cylindrical support wall portion 14 surrounding the through hole 14a is formed on the intermediate wall portion 12.

[0063] The support wall portion 14 is externally fitted with a roller bearing 192 (refer to Figure 1 ), and is the part that supports the roller bearing 192.

[0064] The through hole 15a is formed centered on the axis X3, and a cylindrical support wall portion 15 surrounding the through hole 15a is formed on the intermediate wall portion 12.

[0065] The support wall portion 15 is externally fitted with a tapered roller bearing 193 (refer to Figure 1 ), and is the part that supports the tapered roller bearing 193.

[0066] The through hole 16a is formed centered on the axis X4, and a cylindrical support wall portion 16 surrounding the through hole 16a is formed on the intermediate wall portion 12.

[0067] The support wall portion 15 is externally fitted with a tapered roller bearing 194 (refer to Figure 1 ), and is the part that supports the tapered roller bearing 194.

[0068] As Figure 1 shown, a joint portion 21 with the side cover 30 is provided on the surface of the housing 10 on the side cover 30 side. When observed from the side cover 30 side, the joint portion 21 is formed in a ring shape surrounding the speed change mechanism 120, and the speed change mechanism 120 is housed inside the ring-shaped joint portion 21.

[0069] A bolt hole 21a (first connection point) is formed in the joint portion 21. A plurality of bolt holes 21a are provided at intervals in the circumferential direction, and bolts 91 that penetrate the peripheral portion 35 of the side cover 30 are screwed into each bolt hole 21a.

[0070] The side cover 30 fixed to the joint portion 21 by bolts 91 seals the opening of the annular joint portion 21.

[0071] As Figure 2 shown, on the surface of the outer shell 40 side of the housing 10, there is a joint portion 22 with the outer shell 40. When viewed from the outer shell 40 side, the joint portion 22 is formed in an annular shape, and bolt holes 22a (second connection points) are formed in the joint portion 22. Bolts 92 (refer to Figure 1 ) are screwed into each bolt hole 21a through the peripheral portion 45 of the outer shell 40.

[0072] Inside the outer shell 40 fixed to the joint portion 22 by bolts 92, a torque converter 111 (refer to Figure 1 ) is accommodated.

[0073] As Figure 2 shown, when viewed from the outer shell 40 side, inside the annular joint portion 22, between the through holes 13a and 16a, an oil pump 180 is provided below these through holes 13a and 16a.

[0074] In the housing 10, the oil pump 180 is arranged close to the area below the joint portion 22 in the vertical line direction ( Figure 2 the up - down direction in (a) of

[0075] ) with respect to the installation state of the continuously variable transmission 200. The oil pump 180 is a mechanical oil pump driven by the rotational driving force of an engine (not shown). The rotational driving force of the engine is input to this oil pump 180 via a chain (not shown) of a driving force transmission mechanism (not shown). The oil pump 180 is driven by the input rotational driving force, sucks / pressurizes the oil in an oil pan (not shown) fixed to the lower part of the housing 10, and supplies the hydraulic pressure for the operation of the continuously variable transmission 200 to a hydraulic control circuit (not shown).

[0076] The oil pump 180 is one of the sources of vibration and sound vibration of the continuously variable transmission 200.

[0077] Therefore, as Figure 5 shown, in the existing housing 10A, on the outer peripheral wall portion 11 of the housing 10A, there are strength ribs 420 for ensuring strength against vibration and sound vibration ribs 410 for suppressing sound vibration.

[0078] These strength ribs 420 and sound vibration ribs 410 are portions formed in a plate - like or strip - like shape with a solid middle, and are integrally formed with the housing 10A when casting the housing 10A.

[0079] In the housing 10A, these strength ribs 420 and sound vibration ribs 410 are formed independently of each other.

[0080] In contrast, as Figure 3 andFigure 4 As shown in (a) of FIG.

[0081] Similar to the strength rib 420, the axial rib 25 having the functions of both a strength rib and a sound vibration rib is provided together with the conventional strength rib 420. The axial rib 25 bulges outwards from the surface of the outer peripheral wall portion 11 of the housing 10 and is integrally formed with the housing 10.

[0082] Hereinafter, the arrangement and structure of the axial rib 25 in the housing 10 will be described.

[0083] As shown in Figure 2 (a), in the housing 10, the oil pump 180 is located in the vertical line direction (the up-and-down direction in (a) of Figure 2 (a)) with respect to the installation state of the continuously variable transmission 200 and below the through hole 14a.

[0084] The oil pump 180 is located on the vertical line VL passing through the center (axis X2) of the through hole 14a, and the support wall portion 14 surrounding the through hole 14a is located above the oil pump 180.

[0085] As shown in Figure 1 , in the support wall portion 14, the fixed pulley 141 of the secondary pulley 140 is supported rotatably. And in the support wall portion 15 adjacent to the support wall portion 14, the reduction gear 161 is rotatably supported.

[0086] As described above, the gear 163 on the reduction gear 161 side and the gear 147 on the secondary pulley 140 side are meshed in a rotatable transmission manner.

[0087] When rotating is transmitted between the reduction gear 161 and the secondary pulley 140, meshing reaction forces acting in the directions away from each other (separating directions) act on the gear 147 and the gear 163 respectively.

[0088] Stresses corresponding to the meshing reaction forces of the gear 163 and the gear 147 act on the support wall portion 14 and the support wall portion 15. Therefore, in the housing 10, stresses corresponding to the meshing reaction forces act on the regions around the support wall portion 14 and the regions around the support wall portion 15 (see Figure 2 (b)).

[0089] Here, the region around the support wall portion 14 in the housing 10 is divided into a first region, a second region, a third region, and a fourth region to define the directions in which the stresses corresponding to the meshing reaction forces act.

[0090] As shown in Figure 2 (a), Figure 2(b), the first region, the second region, the third region, and the fourth region are defined by a line segment L1 connecting the center (axis X2) of the gear 147 on one side and the center (axis X3) of the gear 163 on the other side, and a line segment L2 passing through the center (axis X2) of one of the pair of gears (gear 147) and orthogonal to the line segment L1.

[0091] According to the results of stress analysis by experiments and simulations, the influence of the meshing reaction force is greater in the first region and the third region than in the second region and the fourth region. The first region and the third region are the two regions located on the side of the joint portion 22 compared to the line segment L1.

[0092] Moreover, in terms of the influence of the meshing reaction force, the region around the support wall portion 14 (the third region) is larger than the region around the support wall portion 15 (the first region).

[0093] Therefore, in the housing 10, a plurality of radial ribs 26 are connected to the outer periphery of the region (the upper region in the figure) opposite to the joint portion 22 of the support wall portion 14.

[0094] The radial ribs 26 are provided across the support wall portion 14 and the joint portion 22, and a plurality of radial ribs 26 are provided at intervals in the circumferential direction around the axis X2.

[0095] Therefore, the rigid strength around the support wall portion 14 of the housing 10 is increased by these plurality of radial ribs 26.

[0096] Furthermore, in the housing 10, in the vertical line direction with respect to the installation state of the continuously variable transmission 200, looking at the outer peripheral wall portion 11 located on the upper side from the oil pump 180, in the region corresponding to the above-mentioned third region, the influence of the meshing reaction force and the influence of the sound vibration act (refer to Figure 2 the hatched region in (b)).

[0097] Therefore, in the housing 10, axial ribs 25 for increasing the rigid strength are provided on the outer periphery of the outer peripheral wall portion 11 in the region corresponding to the third region.

[0098] As Figure 3 shown, on the outer side surface of the outer peripheral wall portion 11, the axial ribs 25 are provided at a position substantially above the support wall portion 14. The position where the axial ribs 25 are provided is a position for suppressing the meshing reaction force between the gear 147 and the gear 163 (a pair of gears).

[0099] Viewed from the radial direction of the axis X2 passing through the center of the support wall portion 14, the axial ribs 25 are linearly provided along the orientation of the axis X2.

[0100] Viewed from the radial direction of the axis X2, the axial ribs 25 are provided across the outer peripheral wall portion 11 from one side on the housing case 40 side to the other side on the side cover 30 side.

[0101] The axial rib 25 is provided so as to straddle the bolt hole 22a of the joint portion 22 provided on the side of the housing 40 and the bolt hole 21a of the joint portion 21 provided on the side of the side housing 30 (see Figure 4 ).

[0102] A communication hole 25a (hollow portion) that communicates the bolt hole 21a (first connection point) and the bolt hole 22a (second connection point) is formed in the axial rib 25. The communication hole 25a is formed along the center line Cx connecting the center points of the bolt hole 21a and the bolt hole 22a.

[0103] The axial rib 25 is formed in the shape of connecting both the bolt hole 21a and the bolt hole 22a, and the outer peripheral surface 251 (uppermost surface) of the axial rib 25 is located at a position higher than the center line Cx (a position away from the surface of the outer peripheral wall portion 11 of the transmission 1) (see Figure 4 (d), (e)).

[0104] As Figure 2 shown, in the region (third region) where the above-mentioned meshing reaction force acts, when viewed from the axis X2 direction, the axial rib 25 is provided in a positional relationship in which it overlaps with the above-mentioned radial rib 26 in the circumferential phase around the axis X2.

[0105] Therefore, when viewed from the axis X2 direction, the axial rib 25 and the radial rib 26 are located on the line segment R indicating the same phase.

[0106] In the housing 10, the axial rib 25 and the radial rib 26 form a continuous rib while being bent, and through the complementary effects of these axial rib 25 and radial rib 26, the rigid strength around the support wall portion 14 in the housing 10 is further improved.

[0107] Here, the region of the outer peripheral wall portion 11 of the housing 10 corresponding to the third region is located above the oil pump 180, and as described above, it is a position affected by the sound vibration of the oil pump 180.

[0108] In the housing 10A of the existing example, only a solid sound vibration rib 410 is provided in this region, but in the present embodiment, by providing a hollow portion in the axial rib 25, the axial rib 25 has the function of a strength rib and the function of a sound vibration rib.

[0109] Specifically, as Figure 4 shown, a communication hole 25a (hollow portion) that communicates the bolt hole 21a and the bolt hole 22a is formed in the axial rib 25.

[0110] This hollow portion suppresses the propagation of sound vibration and suppresses the release of sound vibration to the outside of the housing 10.

[0111] Further, in the housing 10, the bolt holes 21a, 22a, and communication holes 25a are positioned such that the bolt holes 21a of the joint portion 21 on the side cover 30 side, the bolt holes 22a of the joint portion 22 on the outer housing 40 side, and the communication holes 25a in the axial rib 25 are connected in series.

[0112] Therefore, when the side cover 30 and the outer housing 40 are fixed to the housing 10 with bolts 91 and 92, the coupling pressure of the bolts 91 and 92 acts on a part of the axial rib 25. Thereby, the rigid strength of the hollow axial rib 25 is ensured.

[0113] Figure 5 It is a view showing the housing 10A of the prior example. Figure 5 (a) is a perspective view of the housing 10A observed from obliquely above, (b) is an enlarged view of the main part of (a), and (c) is a view schematically showing the periphery of the rib 410 shown in (b) cut by the plane A.

[0114] Here, a detailed description will be given Figure 4 of the difference between the axial rib 25 (hereinafter simply referred to as rib 25) and Figure 5 the rib 410.

[0115] Figure 5 The rib 410 is a sound vibration rib, and it only needs to have the function of dividing a flat drum-shaped surface. In order to save materials (cost and weight reduction), it has a thin and flat shape.

[0116] On the other hand, Figure 4 the rib 25 is required to have the function of a reinforcing rib in addition to the function of a sound vibration rib.

[0117] In order to enhance the function as a reinforcing rib, an effective method is to thicken its shape in the longitudinal direction and increase the longitudinal section modulus.

[0118] Therefore, Figure 5 the uppermost surface (outer peripheral surface 410a) of the rib 410 is at least a thin shape located lower than the center line Cx passing through the center point of the connection hole (bolt hole 23a).

[0119] In contrast, Figure 4 the rib 25 has the function of a reinforcing rib in addition to the function of a sound vibration rib by making the uppermost surface (outer peripheral surface 251) at least a thick shape located higher than the center line Cx connecting the center points of the connection holes (bolt holes 21a, 22a).

[0120] In addition, in Figure 4 , in order to further strengthen the function as a reinforcing rib, at a position higher than the uppermost point Px of the connection holes (bolt holes 21a, 22a) at a position higher than the center point of the connection holes (center line Cx connecting the center points of the connection bolt holes 21a, 22a),Figure 4 The uppermost part of the rib 25 (outer peripheral surface 251).

[0121] In addition, since the rib becomes thicker, the material used for one rib increases. However, since the strength ribs in other places can be eliminated, the overall material can be reduced.

[0122] In addition, the rib 25 that functions as both a sound vibration rib and a strength rib is connected from the first connection point (bolt hole 21a) to the second connection point (bolt hole 22a) at an extremely short distance (preferably the shortest distance), and the position of the rib is arranged at a position that suppresses the meshing reaction force of a pair of gears. In Figure 4 the position of each connection point is offset from Figure 4 and the positions of the connection points are arranged on the outer wall of the third housing member (housing 10) adjacent to the third region. Figure 5 the outer wall of the third housing member (housing 10) adjacent to the third region.

[0123] In addition, by connecting from the first connection point to the second connection point at an extremely short distance (preferably the shortest distance), the material used can be saved.

[0124] The continuously variable transmission 200 of the present embodiment has the following structure.

[0125] (1) The continuously variable transmission 200 has:

[0126] A housing (transmission case 1) having a first housing member (side cover 30), a second housing member (outer housing 40), and a third housing member (housing 10) sandwiched between the first housing member and the second housing member;

[0127] An oil pump 180 disposed within the housing 10;

[0128] A pair of gears (gear 147, gear 163) disposed within the housing 10.

[0129] On the outer peripheral wall portion 11 (outer wall surface) of the housing 10 adjacent to the pair of gears (gear 147, gear 163), an axial rib 25 (rib) having a linear shape extending from the side cover 30 to the outer housing 40 is formed.

[0130] The axial rib 25 is disposed in a region on a straight line VL extending in the vertical direction from the oil pump 180, and is partially disposed at a position that suppresses the reaction force of meshing of the pair of gears (gear 147, gear 163).

[0131] The axial rib 25 has a shape that connects to both the first connection point (bolt hole 21a) between the first housing member (side cover 30) and the third housing member (housing 10) and the second connection point (bolt hole 22a) between the second housing member (outer housing 40) and the third housing member (housing 10).

[0132] The outer peripheral surface 251 (uppermost surface) of the axial rib 25 is located at a position higher than the center line Cx (a position away from the surface of the outer peripheral wall portion 11 of the transmission 1).

[0133] When configured in this way, by locally arranging the axial ribs 25 at necessary positions, a non-grille-shaped rib that does not need to be provided over the entire outer wall surface of the housing 10 can be formed. Therefore, an increase in weight due to the addition of ribs can be suppressed, and thus, the weight can be reduced.

[0134] In addition, since the local axial rib 25 has a function of suppressing sound vibration and a function of improving strength, as shown in (a) of Figure 5 and (b) of Figure 5 , compared with the case where a sound vibration rib 410 for suppressing sound vibration and a strength rib 420 for improving strength are respectively provided, the number of ribs can be reduced. As a result, the weight can be further reduced.

[0135] That is, in the region directly above the oil pump 180 of the housing 10, since radiated sound such as oil pump noise is generated, in order to suppress the vibration caused by the radiated sound, it is formed in a shape that divides the flat area of the outer wall surface of the housing 10 (the third housing) in a straight line extending vertically from the oil pump 180 (a linear shape extending from the side cover 30 to the outer housing 40), and thus has a function of suppressing sound vibration.

[0136] In addition, a reaction force is generated due to the meshing of a pair of gears (gear 147, gear 163), but since the axial rib 25 is provided at the position where the reaction force is pressed, it can have a function of improving strength.

[0137] In this way, by locally forming the axial rib 25 at a position that also functions as sound vibration and strength, an increase in weight due to the addition of the rib can be suppressed.

[0138] Here, the connection points (the first connection point, the second connection point) are the positions (points) where the housing 10, the side cover 30, and the outer housing 40 are joined to each other by connection members (screws, bolts, etc.).

[0139] When configured as described above and the axial rib 25 is connected to the two connection points (bolt holes 21a, bolt holes 22a), one end of the axial rib 25 is fixed to one of the connection points (bolt hole 21a), and the other end of the axial rib 25 is fixed to the other of the connection points (bolt hole 22a). Thereby, the strength improvement function of the axial rib 25 can be enhanced.

[0140] The continuously variable transmission 200 of the present embodiment has the following structure.

[0141] (2) Divide the area around a pair of gears (gear 147, gear 163) inside the housing 10 into a first area, a second area, a third area, and a fourth area. When defining the position for suppressing the meshing reaction force, the position for suppressing the meshing reaction force is the position of the outer peripheral wall portion 11 (outer wall surface) of the housing 10 adjacent to the third area.

[0142] Here, as Figure 2 (a), Figure 2 (b) shows, the first area, the second area, the third area, and the fourth area are defined using a line segment L1 connecting the centers (axis X2) of one of the pair of gears (gear 147) and the centers (axis X3) of the other (gear 163), and a line segment L2 passing through the center (axis X2) of one of the pair of gears (gear 147) and perpendicular to the line segment L1.

[0143] The first area is the area that is located in the front side (power output side) when viewed from the meshing position side of the pair of gears (gear 147, gear 163), and is located in the front side (close to the outer peripheral wall portion 11 side) when viewed from the outer wall side (outer peripheral wall portion 11 side).

[0144] The second area is the area that is located in the front side (power output side) when viewed from the meshing position side of the pair of gears (gear 147, gear 163), and is located in the inner side (far from the outer peripheral wall portion 11 side) when viewed from the outer wall side (outer peripheral wall portion 11 side).

[0145] The third area is the area that is located in the inner side (power input side) when viewed from the meshing position side of the pair of gears (gear 147, gear 163), and is located in the front side (close to the outer peripheral wall portion 11 side) when viewed from the outer wall surface side (outer peripheral wall portion 11 side).

[0146] The fourth area is the area that is located in the inner side (power input side) when viewed from the meshing position side of the pair of gears (gear 147, gear 163), and is located in the inner side (far from the outer peripheral wall portion 11 side) when viewed from the outer side wall (outer peripheral wall portion 11 side).

[0147] When configured in this way, the axial ribs 25 are locally arranged at the position for suppressing the meshing reaction force, i.e., the third area.

[0148] Thereby, while preventing the weight of the housing 10 from increasing, the rigid strength around the outer peripheral wall portion 11 of the housing 10 can be ensured and the radiated sound caused by sound vibration can be suppressed.

[0149] The continuously variable transmission 200 of this embodiment has the following structure.

[0150] (3) The first connection point and the second connection point are arranged at positions on the outer peripheral wall portion 11 (outer wall surface) of the housing 10 (third housing component) adjacent to the region (third region) where the meshing reaction force acts.

[0151] When configured in this way, the axial rib 25 and the radial rib 26 connected to both the first connection point (bolt hole 21a) and the second connection point (bolt hole 22a) are provided in a positional relationship where their phases in the circumferential direction around the axis X2 overlap.

[0152] Accordingly, in the housing 10, the axial rib 25 and the radial rib 26 form a continuous rib that bends, and due to the complementary effects of these axial rib 25 and radial rib 26, the rigid strength around the support wall portion 14 of the housing 10 is further improved.

[0153] The continuously variable transmission 200 of the present embodiment has the following structure.

[0154] (4) The axial rib 25 has a hollow portion (communication hole 25a).

[0155] When configured in this way, by providing a hollow portion in the axial rib 25 where there is no connecting member or the metal of the housing itself, the sound vibration suppression effect can be improved by the influence of the hollow portion. This is based on the fact that sound is difficult to transmit due to the presence of an air layer.

[0156] In addition, as a method for manufacturing the hollow portion, for example, a method of slightly deepening a bolt hole (screw hole) to form the hollow portion, or a method of forming a hollow portion that penetrates between two bolt holes can be adopted. In addition, the manufacturing method of the hollow portion is not limited to this method.

[0157] The continuously variable transmission 200 of the present embodiment has the following structure.

[0158] (5) The hollow portion (communication hole 25a) is formed by a through hole connecting the first connection point (bolt hole 21a) and the second connection point (bolt hole 22a).

[0159] When configured in this way, by being through, the volume of the hollow portion, that is, the volume of the air layer increases, and thus the sound vibration suppression effect is improved.

[0160] The continuously variable transmission 200 of the present embodiment has the following structure.

[0161] (6) The third housing component (housing 10) has a support portion (support wall portion 14) that supports one of a pair of gears (gear 147) and a radial rib 26 that connects its peripheral wall portion (outer peripheral wall portion 11).

[0162] When configured in this way, since the radial rib 26 connects the support wall portion 14 and the outer peripheral wall portion 11, the support wall portion 14 can be easily positioned relative to the outer peripheral wall portion 11. As a result, the rigidity of the support wall portion 14 is increased, and thus, the gear 147 can be supported well.

[0163] In the above embodiment, the case where the driving force transmission device is an automatic transmission for a vehicle is illustrated. The driving force transmission device of the present invention is not limited to an automatic transmission for a vehicle.

[0164] It can also be applied to a gear set composed of a plurality of gears, and at least one gear can splash the oil in the storage box of the gear set to form a device. As such a device, a reduction device that decelerates and outputs the input rotation is illustrated.

[0165] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the forms shown in these embodiments. It can be appropriately changed within the scope of the technical idea of the invention.

Claims

1. A power transmission device, comprising: A housing having a first housing member, a second housing member, and a third housing member sandwiched between the first housing member and the second housing member; A pair of gears constituted by gears provided on a second axis (X2) and a third axis (X3) and arranged within the housing; A first axis (X1) to which rotational driving force from a drive source disposed diagonally below the pair of gears is input; An oil pump arranged within the housing and disposed vertically below the pair of gears, wherein An extending portion is formed on an outer wall surface of the third housing member at a position adjacent to the pair of gears, the extending portion extending along a direction from the first housing member toward the second housing member and protruding outward from the housing; The extending portion has a part disposed vertically above the oil pump; The extending portion has a part disposed vertically above the pair of gears; The extending portion has a part disposed on the power input side when viewed from the meshing position side of the pair of gears.

2. The power transmission device according to claim 1, wherein The extending portion has a hollow portion.

3. The power transmission device according to claim 2, wherein The axial length of the hollow portion is longer than the length of the portion of the bolt inserted into the housing.

4. The power transmission device according to any one of claims 1 to 3, wherein The center of one of the pair of gears is arranged separated from a vertical line passing through the center of the other of the pair of gears.

5. The power transmission device according to any one of claims 1 to 3, wherein The oil pump and the pair of gears are arranged within the third housing member.

6. The power transmission device according to any one of claims 1 to 3, wherein The extending portion is arranged separated from a vertical line passing through the axial center of the input side.

7. The power transmission device according to any one of claims 1 to 3, wherein The uppermost surface of the extending portion is at a position higher than the uppermost point of the connection hole located at the uppermost side in the gravitational direction among the connection holes between the first housing member and the third housing member.

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