JPS60157563A - Automatic transmission - Google Patents

Abstract

PURPOSE:To facilitate the alignment of the shaft axes at the time of assembly as well as to eliminate the differential pressure by a single breather hole between two devices in an arrangement in which an overdrive device is interposed between a torque converter and an underdrive device. CONSTITUTION:Adjacent to a torque converter 1 which is driven by the crankshaft 8 of an engine, an oil pump 71 and an overdrive device 2 are disposed, and further adjacent to said device 2, an underdrive device 3 is disposed. The transmission case 18 which houses elements that make up said device is connected to the overdrive case 16 by a faucet joint, and pump body 20, pump cover 21 and said two cases 16, 18 are connected into one piece by a through bolt 22. The case 16 is provided with a communicating hole 111 that communicates the interior space of the two drive devices 2, 3, and a breather hole 103 drilled in the case 18 is communicated to a breather hole 82 which is connected to the interior space of the overdrive device 2.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a self-excited transmission in which an overdrive device is arranged between a hydraulic torque converter and an underdrive device.

Prior art automatic transmissions automatically switch reduction ratios in relation to 11Ii speed and engine load. Automatic transmissions usually consist of a torque converter and an underdrive device that is connected to the torque converter to obtain a reduction ratio of 1 or more, but in recent years automatic transmissions that can also provide overdrive (speed-increasing drive) have been developed. Demand is also increasing from the standpoint of fuel savings and reduction of harmful components in exhaust gas. When an overdrive device is added to an automatic transmission consisting of a torque converter and an underdrive device, the required strength of the overdrive device's gears and the required capacity of the friction material are reduced, which is advantageous in terms of durability and cost. In order to It is preferable to connect it to the input side of the (front-end type). Furthermore, since the automatic transmission includes a torque converter and a hydraulic control device, an oil pump is required to generate working hydraulic pressure for these devices. Since the oil pump must be connected to and driven by the pump impeller of the torque converter, in the case of a front-mounted automatic transmission, the oil pump is installed in the wall that partitions the torque converter and the overdrive device.

Furthermore, instead of configuring an automatic transmission having an overdrive separately from a known underdrive device, it is possible to utilize such a known underdrive device and configure it with minimal changes to the underdrive device. if,
In producing automatic transmissions with overdrive,
Many parts are common to those used when producing automatic transmissions without overdrive, reducing the number of new parts required.
Parts management becomes extremely easy.

It is also a well-known fact that simple transmissions are superior in reliability, and by adding a simple overdrive device to the reliability of a conventional underdrive device, a highly reliable automatic transmission can be constructed. I can do it. For this reason, a device including an overdrive mechanism is placed between the underdrive device and the torque converter, which is advantageous in terms of input torque. be assembled into. In addition, in automatic transmissions without an overdrive device, the input shaft of the underdrive device supported by the oil pump body is replaced by an overdrive device in automatic transmissions in which the overdrive device is disposed between the underdrive device and the torque converter. Supported by the case. Further, in this case, since the overdrive case is fitted into the underdrive device, it is possible to more firmly support the input shaft of the underdrive device. Such an overdrive case becomes a partition wall that partitions the internal space of the overdrive device from the internal space of the underdrive device.

Therefore, the internal space of the overdrive device is partitioned on both sides, and the elements within the overdrive device are housed in one closed space.

In addition, changes in the pressure in the space housing the overdrive device and the underdrive device cause oil in the automatic transmission to be blown out through a fella tube into which an oil level gauge for measuring the automatic level is inserted. Therefore, in order to minimize the difference between the pressure in the space and the atmospheric pressure, a breather circuit connected to the atmosphere is required. Furthermore, the oil that has lubricated and cooled the overdrive device and underdrive device is dissipated to the surroundings by the centrifugal force from the rotating body and adheres to the inner wall surrounding the overdrive case or transmission case in the radial direction, so the breather circuit The ends of these within! If formed directly on the lx, the oil may close the breather circuit or cause oil leakage. Therefore, the breather circuit must be connected to the overdrive device and the underdrive device from the axial direction rather than the radial direction of the automatic transmission through a circuit that is complexly formed in the oil pump body and the oil pump cover, and The overdrive device and underdrive device are provided in an overdrive case independent of each other.
If the transmission case is housed within these spaces, consideration must be given to not providing individual breather devices, but this would complicate the housing configuration and increase costs. The problem arises.

Problems to be Solved by the Invention The objects of the present invention are as follows: (a) an overdrive device is disposed between a torque converter and an underdrive device; (b) In an automatic transmission in which the overdrive case supports the input shaft of the underdrive device, alignment of the oil pump, overdrive device, and underdrive device is easy. Another object of the present invention is to provide an automatic transmission that can omit the need to provide a breather port in each of an overdrive device and an underdrive device.

Means for Solving the Problems To achieve this object, the automatic transmission of the present invention comprises a hydraulic torque converter driven by the crankshaft of the engine, connected on the input side to the output of the hydraulic torque converter. an overdrive device that transmits power from the side to the output side at a reduction ratio of 1 or less than 1 and is housed in an overdrive case; an oil pump body and an oil pump cover that extend between the hydraulic torque converter and the overdrive device; An oil pump that generates working hydraulic pressure, descended from
An underdrive device that transmits power on the input side to the output side at a plurality of reduction ratios of 1 or more, is housed in a transmission case, and the transmission case is connected to an overdrive case by a spigot, and an overdrive device and an underdrive device. an overdrive case that extends between the overdrive case and supports the input shaft of the underdrive neck; a communication hole formed in the overdrive case that communicates the internal space of the overdrive device with the internal space of the underdrive device; and a transmission. A breather port provided in the case, a breather passage formed in the overdrive case that connects the breather port to the internal space of the overdrive device or underdrive device, and a breather passage that passes through the oil pump body, oil pump cover, and overdrive case. It has a through bolt that reaches the transmission case and connects the oil pump body, oil pump cover, overdrive case, and transmission case.

Example The present invention will be explained with reference to the embodiments shown in the drawings.

FIG. 2 shows an automatic transmission that is commercially available before the application is filed and does not include an overdrive device. The hydraulic torque converter 1 includes a pump impeller 5, a turbine runner 6, and a stator 7. The pump impeller 5 is connected to a crankshaft 8 of an engine (not shown), and the turbine runner 6
is connected to the turbine shaft 9a. Torque converter l is surrounded in the circumferential direction of turbine shaft 9a by housing +7a.

The rear of torque converter 1 (hereinafter, the side closer to the engine is referred to as [1]
)iJ, the side farthest from the engine is called the "back". ) are partitioned by the oil pump body 20. The oil pump cover 21 is arranged adjacent to the oil pump body 20 and defines a pump chamber of the oil pump 71 together with the oil pump body 20. The oil pump gear 50 of the oil pump 7e is connected to the pump impeller 5. Passage 72 formed within oil pump body 20
is connected to the suction side of the oil pump 71 at one end, and connected to the oil pan 75a at the other end via a passage in the oil pump cover 21 and the transmission case 18.
connected to the inside.

Beyond the oil pump 71 and adjacent to the oil pump cover 21, an underdrive device 3 with three forward speeds and one reverse speed is installed 5 coaxially with respect to the torque converter l. The turbine shaft 9a serves as an input shaft of the acidatribe device 3. The underdrive device 3 has its front portion covered by an oil pump cover 21 and a transmission case 18. Oil pump cover ”=-20, oil pump cover 21, and transmission case 1
8 are connected to each other by a plurality of bolts 22a.

The turbine shaft 9a' is connected to a clutch cylinder 65, and a multi-disc clutch 24 is provided between the clutch cylinder 65 and the intermediate shaft 29. The hub 66 is connected to a clutch cylinder 65, and a multi-disc clutch 25 is provided between the hub 66 and the sun gear shaft 30. A multi-disc brake 26 and a series connection of a one-way clutch 61 and a multi-disc brake 60 are provided between the sun gear shaft 30 and a support 31 fixed to the transmission case 18 .

A sun gear 32 is formed on the sun gear shaft 30. Sun gear 32 meshes with planetary pinions 34 and 37, one planetary pinion 34 meshes with link gear 35.
The other planetary pinion 37 meshes with the link gear 38. That is, sun gear 32, planetary pinion 34, and link gear 35 and sun gear 32, planetary pinion 37, and link gear 38
A 6° ring gear 35, which constitutes a two-row planetary gear set consisting of the following, is connected to the intermediate shaft 29 via a flange 67. Further, the planetary pinion 34 is connected to the carrier 3
The planetary pinion 37 is rotatably supported on the pinion shaft 59 of the carrier 36, and the planetary pinion 37 is supported around the pinion shaft 68'' of the carrier 36 by ν, Ijl r+tj. The output shaft 39 of the underdrive device 3 is connected to the link gear 38 and the gear rear 33. A multi-disc brake 27 and a one-way clutch 28 are provided between the carrier 36 and the transmission case 18.

The lower part of the underdrive device is covered by an oil pan 75a. A hydraulic control device 4a (only a portion is shown) is disposed inside the oil pan 75a to control the hydraulic pressure supplied to the hydraulic servo (cylinder) of the underdrive device.

A breather port 103 is provided at the front upper end of the transmission case 18, and a plug 104 is attached to the breather port. An axial passage +05 is formed above the oil pump cover 21, and an axial passage +06 is formed below. Aisles 105 and 106
A passage 107 is bent and formed between the oil pump body 20 and the oil pump cover 21 in order to connect the oil pump body 20 and the oil pump cover 21. In this way, atmospheric pressure is transferred from the breather port 103 to the underdrive device 3 via passages 105, 107, and 106.
is guided from the axial direction into the lower part of the This configuration of the breather circuit is beneficial to prevent oil leakage.

FIG. 1 is a longitudinal sectional view of an automatic transmission when an overdrive device is added. The parts corresponding to Figure 2 are shown in Figure 2.
The same reference numerals as in the figure are used to omit the explanation.

The turbine shaft 9 plays the role of the output shaft of the torque converter 1 as well as the input shaft of the overdrive device 2, and is connected to the carrier 0 of the planetary gear device in the overdrive device. The carrier 10 is connected to the pinion shaft 4
9, and needle bearings 43 and 44 are provided in two rows in the axial direction on the outer periphery of the pinion shaft 49. The planetary pinion 14 has these two needle bearings 43
．． rotatably supported by the pinion shaft 49 via 44,
It meshes with sun gear 11 and link gear 15.

Thrust washers 51, 52 are provided between the planetary pinion 14 and the carrier 10, respectively. A sun gear shaft 78 on which the sun gear 11 is formed is connected to the clutch cylinder 63. The hub 64 is spline fitted to the clutch cylinder 63. A multi-disc clutch 12 is provided between the clutch cylinder 63 and the carrier 10, and a one-way latch I3 is provided between the sun gear shaft 78 and the carrier 10, and includes the hub 64 and the overdrive device ξ. A multi-plate brake 19 is provided between the overdrive case 6 and the overdrive case 6. Housing 1
7 has an extension portion 77 that covers the periphery of the torque converter 1 and has an inner surface shaped like a cylindrical side surface. The overdrive case 16 has a cylindrical side surface, and is disposed such that the side surface fits into the inner surface of the extension portion 77 . Also, the overdrive case 16 is the transmission case 1.
8 with a spigot, thereby making it easy to align the overdrive device 2 and the underdrive device. The flange 53 connected to the ring gear 15 is
The input shaft 23 of the underdrive device 3 has a spline. The input shaft 23 is disposed coaxially with the turbine shaft 9 and is connected to the aforementioned clutch cylinder 6 of the underdrive device 3.
It is directly connected to 5. The overdrive case 16 has a radially extending portion 120 for supporting the input shaft;
This portion 120 partitions the internal space of the overdrive device 2 from the internal space of the underdrive device 3. A bearing 54 is disposed between the turbine l1II119 and the input state +23, and a washer 56 is disposed between the carrier 10 and the flange 53. A plurality of through bolts 22 are connected to the oil pump body 20, the oil pump cover 21. and overdrive case 16 in order.
through which it reaches the transmission case 18 and connects them together in the axial direction.

In such an automatic shift mode, the relationship between the shift position Nt, the gear stage, and the activation state of each clutch and brake is shown in the chart of FIG. In Fig. 3, P is parking range, R is reverse range, N is neutral range, D is drive range, 2 is second range, L is low range, ○ is engaged, × is released, and Rc is locked. state, OR indicates an overrun state, and * indicates a state in which power is not being transmitted. Also, 0.
0. means overdrive.

Next, overdrive device 2 and underdrive device 3
We will explain the lubrication and cooling of each element that makes up the system.

The oil pressurized by the oil pump 7I is adjusted to a predetermined pressure in the hydraulic control device 4. The pressure-regulated oil is supplied to each element of the overdrive device 2 and the underdrive device 3 through the oil passage 45 of the transmission case 18 and the oil passage 46 of the intermediate shaft 29, and antiperspirants J and cools them. Needle bearing 43.4
Special oil channels are formed in the overdrive device 2 for lubrication and cooling in the vicinity of the overdrive device 2 . That is,
A space defined by the input shaft 23 and the turbine shaft 9 forms an oil chamber 55 . The oil chamber 55 is connected to the inner hole of the input shaft 23 via the hole 42 provided in the side wall of the input shaft 23 . The oil passage 40 extends in the radial direction of the carrier 10, is connected to an oil chamber 55 at one end, and is closed by a plug 58 at the other end.

An oil passage 41 extending in the axial direction is provided inside the pinion shaft 49 . The oil passage 41 is connected to the oil passage 40 at one end and is blocked by a plug 57 at the other end. Almost in the longitudinal center of the pinion shaft is oil! 11
548 is formed, and this oil passage 48 is connected to the oil passage 4 at one end.
1 and a needle bearing 43.1 at the other end.
It has reached the middle of 44. The elements in the vicinity of the needle bearings 43, 44 are thus lubricated and cooled by oil at a certain pressure supplied via the bore 42, the oil chamber 55 and the oil passages 40, 41, 48.

FIG. 4 is a left side view of the overdrive case 16 (torque converter 1 flight u), FIG. 5 is a sectional view taken along the line ■-■ in FIG. 4, and FIG. 6 is a right side view of the overdrive case 16. (underdrive device 3 side) are shown. In FIGS. 4 and 6, the vertical direction corresponds to the vertical direction, and in FIG. 5, the left end corresponds to the torque converter l side, and the right end corresponds to the underdrive device 3 side. 81 is
This is a hole for the bolt 22 to pass through. A breather passage 82 connects the breather port 103 at the front upper end of the transmission case 18 and the passage 105 of the oil pump cover 21 .

83 is Breather 0103 via Breather Tsuji@82
This is an oil return passage provided below the breather passage 82 in order to prevent oil from returning. The oil return passage 83 is connected to the breather passage 82 at the rear end via a groove 88 formed in the end surface of the overdrive case 16 on the underdrive device 3 side, and is connected to the passage +07 at the front end. . The oil that may accumulate in the breather passage 82 in this way is
The oil is returned from the breather port 103 through the oil return passage 83 without getting sick. 84 is a supply passage for supplying oil from the hydraulic control device 4 to the torque converter 1;
85 transfers oil from the torque converter 1 to the hydraulic control device 4
This is a discharge passageway for returning to. 86 and 87 are suction passages that guide oil in the oil pan 75 installed at the bottom of the underdrive device 3 to the oil pump 71;
This is a discharge passage that guides the oil pressurized by the oil pump 71 to the hydraulic control device a4 at the bottom of the underdrive device/13. The suction passage 87 is connected to the oil passage 72 at the front end via the oil passage of the oil pump cover 21, and is connected to the oil passage 72 at the rear end via the oil passage 76 and the oil passage (
(not shown). oil pump cover 2
In order to be properly connected to the oil passage of No. 1, the suction passage 87 is
It is formed at the lowermost end of the overdrive case and has an enlarged portion 92 at the front end. The υ1 outlet passage 93 is formed at the lowest end of the periphery of the overdrive case 16 along with the suction passage 87, and is
It communicates with the lower part of the space inside the oil pant 6, and is connected to the inside of the oil pant 5 at the rear end. At least the lower part of the discharge passage 93 is located below the lowermost rotating element of the overdrive device 2, in this case the clutch cylinder 63.
There are 4.

The rotation of the rotating element in the Patrive device 2 agitates the oil and becomes an impediment to the oil discharge through the outlet passage 93, but the oil located at least at the bottom of the discharge passage 93 is overdriven. At least a part of the oil accumulated in the lower part of the internal space of the overdrive device 2 is discharged without being agitated by the rotating elements of the overdrive device 2, and as a result, the oil can be smoothly discharged from the overdrive device 2. The suction passage 87 and the discharge passage 93 are separated by a wall 98. 101 more
102 is a passage connecting the hydraulic control device 4 and the clutch cylinder 63 and guiding the hydraulic pressure, and 102 is a passage connecting the hydraulic control device 4 and the clutch cylinder 65 and guiding the hydraulic pressure. Passage 82.83, 84, 85, 86, 87.91.101
Both pass through in the axial direction around the overdrive case 16.

As can be seen from the left side view and right side view of FIGS. 4 and 6, the angular intervals of the bolt penetration holes 81 in the circumferential direction of the overdrive case 16 are different.
A plurality of bolts 22 are passed through the holes 81, and the oil pump body 20, oil pump cover 21. When overdrive case 16 and transmission case 18 are assembled, 82 to 87 are automatically connected to their corresponding passages on both sides of overdrive case 16 in the axial direction.

Furthermore, the overdrive case 16 has a plurality of communication holes 11.
1 is passage 82.83, 84, 86, 87.9+, 93
．． 101 is formed concentrically on the inner side in the radial direction than the peripheral portion where the periphery 101 is formed. As a result, the internal spaces of the overdrive device 2 and the underdrive device 3, which are partitioned from each other by the portion +20 of the overdrive case 16 on the support side of the input shaft 23 of the underdrive device 3, communicate with each other through the communication hole 111. , the air pressures in the rectangular spaces are maintained equal to each other.

Effects of the Invention According to the present invention, the air space inside the overdrive device and the air space inside the underdrive device are provided with a hole that communicates with each other to maintain both air spaces at the same pressure. A breather port connects one of the air spaces to the atmosphere. As a result, when producing automatic transmissions with overdrive, there is no need to provide a breather port in the overdrive device that is added between the torque converter and the underdrive device, and the auxiliary air space is Seal damage and oil leakage can be prevented by maintaining the air pressure at approximately atmospheric pressure.

Further, in the present invention, the breather port of the amplifier drive device used in the 11M transmission without overdrive can also be used in the automatic transmission with overdrive, which is advantageous in manufacturing.

Furthermore, a breather passage that communicates the breather port of the amplifier drive device with one of the air spaces is formed in the overdrive case, so the length of the breather passage is increased, making it difficult for oil to leak from the breather port. .

In the present invention, a through bolt passes through an oil pump body, an oil pump cover, and an overdrive case to reach a transmission case, and connects these oil pump body, oil pump cover, overdrive case, and transmission case to each other, and overdrives the overdrive. The case and transmission case are connected to each other with a spigot, making it easy to assemble! Alignment when pulling is very accurate and easy.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a self-excited transmission according to the present invention when an overdrive device is added, Fig. 2 is a longitudinal sectional view of a known automatic transmission without an overdrive device, and Fig. 3 is a shift position. 4 is a left side view of the overdrive case, FIG. 5 is a sectional view taken along the line ■-■ in FIG. 4, and FIG. The figure is a side view of the overdrive case. DESCRIPTION OF SYMBOLS 1...Hydraulic torque converter, 2...Overdrive device, 3...Amplifier drive device, 6...Turbine runner, 8...Crankshaft, 16...Overdrive case, 18... transmission case,
20... Oil pump body, 21... Oil pump cover, 22... Bolt, 23... Input shaft, 63
...Clutch cylinder, 71...Oil pump, 8
2... Breather passage, 103... Breather port, 11
1...Communication hole, 120...part. Figure 4 Figure 5 Figure 1 Figure 6 Procedural amendments January 11, 1985 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case 1982 Patent Application No. 262983 2, Name of the invention Automatic transmission 3, Amendment Patent Applicant (320) Name: Toyota Motor Corporation 4, Agent
Person Specifications, 1, page 3, line 18 to page 8, line 2 “Preferred.”
It is. J has been corrected as follows: ``Preferable (for example, Japanese Patent Application Laid-Open No. 52-52067). Problems to be Solved by the Invention An object of the present invention is to correct the overdrive device between the torque converter and the underdrive device. In automatic transmissions installed in the oil pump, overdrive device Kj. The purpose of this assembly is to improve efficiency and eliminate the need to provide a breather port for each overdrive device and underdrive device.j 2 Page 22, line 12 to page 24, line 2 [Invention The effect of
... becomes easier. Correct J as follows. ``Advantageous Effects of the Invention Rather than configuring an automatic transmission device for overdrive separately from the already known underdrive device, it can be configured using an underdrive device and with minimal changes to this underdrive device. For example, when producing automatic transmissions with overdrive, many parts can be used that are common to those used when producing automatic transmissions without overdrive.
The number of new parts required is reduced and productivity is improved. Furthermore, it is a well-known fact that simple transmissions are superior in reliability, and by adding a simple overdrive device to the reliability of a conventional underdrive device, a highly reliable automatic transmission can be constructed. I can do it. For this reason, a device including an overdrive mechanism is placed between the underdrive device and the torque converter, which is advantageous in terms of input torque, but in the present invention, the overdrive device is assembled to the underdrive device by a spigot.
The alignment between the overdrive device and the underdrive device can be made accurate and easy. In addition, in an automatic transmission without an overdrive device, the input shaft of the underdrive device supported by the oil pump body is replaced by In automatic transmissions, the input shaft of the underdrive device is supported by an overdrive case, and the overdrive case is connected to the underdrive device by a spigot, so the support of the input shaft of the underdrive device is extremely strong. In the transmission, an oil pump is required to generate working hydraulic pressure for the torque converter and the hydraulic control device.The oil pump is advantageously driven in connection with the pump impeller of the torque converter. Therefore, if the oil pump is mounted on the pump impeller, the oil pump body and oil pump case serving as the housing of the oil pump become a wall separating the torque converter and the overdrive device.Furthermore, the underdrive device The internal space of the overdrive device is separated from the internal space of the underdrive device by the part of the overdrive case that supports the input shaft of the overdrive device, so the elements within the overdrive device are housed in one closed space. .Changes in the pressure in the space housing the overdrive device and underdrive device may damage the oil seal installed in the automatic transmission.
This may cause the oil in the automatic transmission to blow out from the feeder tube into which the oil level gauge that measures the oil level in the self-excited transmission is inserted. Therefore, in order to minimize the pressure difference between the pressure in the space and the atmospheric pressure,
A breather circuit connected to the atmosphere is required, but if the internal space of the overdrive device is partitioned from the internal space of the underdrive device and becomes one closed space, a breather circuit is required for the overdrive device and the underdrive device. Providing a breather device complicates the structure of the housing and increases costs. In the present invention, the air space inside the overdrive device and the underdrive device? +
A hole is provided to communicate with the air space of section f'3 to maintain both air spaces at equal pressure, and a breather port of the underdrive device communicates one of the air spaces with the atmosphere. As a result, when producing an automatic transmission with an overdrive, there is no need to provide a breather port in the overdrive device that is added between the torque converter and the underdrive device, and the breather port of the underdrive device allows both air spaces to be closed. Damage to the seal and oil leakage can be prevented by maintaining the pressure at approximately atmospheric pressure. Furthermore, in the present invention, the breather port of an underdrive device used in an automatic transmission without overdrive is also used in an automatic transmission with overdrive, so it is a descendant in terms of manufacturing. Furthermore, since the breather passage that communicates the breather port of the underdrive device with one of the air spaces is formed in the overdrive case, the length of the breather passage is increased, making it difficult for oil to leak from the breather port.

Claims (1)

[Claims] A hydraulic torque converter driven by the crankshaft of an engine, connected to the output part of the hydraulic torque converter on the input side, transmits power from the input side to the output side with a reduction ratio of 1 or less than 1, and is installed in an overdrive case. An overdrive device to be accommodated, an oil pump that has an oil pump body and an oil pump cover that extend between the hydraulic torque converter and the overdrive device, and generates working oil pressure, There is an underdrive device that is housed in a transmission case and the transmission case is connected to the overdrive case by a spigot, and an underdrive device that extends between the overdrive device and the underdrive device. the overdrive case that supports the input shaft of the overdrive case; a communication hole formed in the overdrive case that communicates the internal space of the overdrive device with the internal space of the underdrive device; and a breather port provided in the transmission case. , a breather passage that is formed in the overdrive case and connects the breather port to the pg section 1-4j of the overdrive device or underdrive device, and passes through the oil pump body, oil pump cover, and overdrive case to the transmission case. An automatic transmission characterized by having a through bolt that connects the oil pump body, oil pump cover, overdrive case, and transmission case.