JPH0686895B2 - Automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an automatic gear shift system which is mounted on an automobile and automatically shifts gears by switching a transmission path of an engine output according to a driving state. The invention relates to the construction of a new gear train in a machine, in particular a transmission of this kind.

(Prior Art) An automatic transmission using a planetary gear mechanism is generally used as an automatic transmission for automobiles. However, when an attempt is made to increase the number of gears for a truck or the like, a planetary gear mechanism is used. Therefore, the structure of the gear train becomes extremely complicated, and the size of the entire transmission becomes large. Therefore, a gear train structure conventionally used in a manual transmission, that is, a plurality of gear trains having different gear ratios are arranged in parallel between two parallel shafts, and one of the gear trains is selectively in a power transmission state. The adoption of an automatic transmission that uses a gear train that achieves multiple gears by selecting the gear trains, and that automatically shifts gears by selecting this gear train using a friction clutch. Conceivable. However, when an automatic transmission is configured using this type of gear train, the following problems occur. That is, the gear shifting operation is performed by switching one gear train from the power transmission state to the power cut-off state and simultaneously switching the other gear trains from the power cut-off state to the power transmission state. The disengagement operation of the friction clutch and the engagement operation of the friction clutch for the latter gear train are required. However, if the timings of the disengagement and engagement operations are not appropriate, for example, a state where two friction clutches are engaged at the same time occurs. A so-called gear shift shock occurs, or the two friction clutches are both released to bring the transmission into a neutral state, which causes a problem such as an engine rotation blow-up phenomenon. Further, in order to prevent such a problem, if the two friction clutches are disengaged and engaged during gear shifting at appropriate timings, the control circuit becomes extremely complicated.

By the way, as will be described later, the automatic transmission according to the present invention selectively brings a plurality of gear trains arranged in parallel between two parallel shafts into a power transmission state by using a friction clutch and a one-way clutch. There is a gear type transmission device disclosed in Japanese Patent Laid-Open No. 225244/1983 as a device in which a plurality of gear trains are arranged in parallel between two parallel shafts and which is provided with a power on / off clutch and a one-way clutch. However, this transmission uses a manually operated synchronizer as a means for connecting a gear that is in a floating state to the shaft to the shaft, and the so-called front engine front where the output shaft is not coaxial with the engine output shaft. The present invention relates to a transmission for a drive vehicle, which is different in basic model from the automatic transmission according to the present invention.

(Object of the Invention) The present invention solves the above problems in an automatic transmission, particularly an automatic transmission adopting a gear train structure in which a plurality of gear trains are arranged in parallel between two parallel shafts. By realizing a structure that makes it easy to control the operation timing of the friction clutch during operation, the overall structure is made compact as an automatic transmission with multiple gears, and the shift control shock and engine rotation are controlled by a simple control circuit. An object of the present invention is to provide an automatic transmission in which a gear shifting operation is favorably performed without causing an uphill or the like.

(Structure of the Invention) The automatic transmission according to the present invention is characterized by having the following structure in order to achieve the above object.

That is, first, an input shaft connected to the engine output shaft via a torsion spring or a torque converter, an output shaft arranged coaxially behind the input shaft, and a counter shaft arranged in parallel with these shafts. With. And
A power transmission path including a first gear train including a first gear on the input shaft and a second gear on a counter shaft meshing with the gear as a friction clutch for connecting and disconnecting a plurality of power transmission paths between the shafts. The first friction clutch that engages and disengages the first friction clutch and the first friction clutch that allows the rear end of the input shaft to transmit rotation from the input side to the output side
A second friction clutch that connects and disconnects a power transmission path that includes a second gear train that includes a third gear provided via a one-way clutch and a fourth gear on the counter shaft that meshes with the third gear; A third friction clutch provided at the front end that connects and disconnects the power transmission path from the input shaft to the output shaft via the first one-way clutch, and a fifth gear and a fifth gear at the rear end of the counter shaft. A fourth friction clutch that connects and disconnects a power transmission path including a third gear train consisting of a sixth gear on the output shaft and a second one-way clutch that allows rotation transmission from the input side to the output side is provided.

According to the above configuration, if the gear ratios of the three gear trains are appropriately set, as a power transmission path from the input shaft to the output shaft by selectively engaging the first to fourth friction clutches, A route like That is, the path passing through the second gear train, the counter shaft and the third gear train (first speed), the path passing through the first gear train, the counter shaft and the third gear train (second speed), directly from the input shaft. A path through which power is transmitted to the output shaft (third speed) and a path through the first gear train, the counter shaft, and the second gear train (fourth speed) are obtained. It is possible to configure the forward speed. And, in particular, according to the above configuration, the action of the first and second one-way clutches causes 1-2,
During the gear shift of 2-3 and 3-4, the gear stage is switched by engaging or releasing one friction clutch.

(Advantages of the Invention) Since the automatic transmission according to the present invention has the above-described configuration, the adoption of the parallel two-shaft gear train and the fact that four forward gears can be obtained by three gear trains are combined. Thus, the whole is made compact as compared with other automatic transmissions having the same number of gears. In particular, since each shift speed is changed only by the operation of one friction clutch, the troublesomeness of optimally setting the operation timings of the plurality of friction clutches by using a complicated control circuit is reduced, and a simple control circuit is provided. In addition, an automatic transmission can be realized in which a favorable gear shifting operation is performed without causing a gear shift shock or a rise in engine rotation.

(Example) Hereinafter, the Example of this invention is described. It should be noted that in the following embodiments, six forward gears are obtained by four gear trains, and the fifth gear, the sixth gear, and the third gear composed of these gears in the above description are provided. Columns,
And the fourth friction clutch, which connects and disconnects the power transmission path including the gear train, includes a seventh gear 57 and an eighth gear in the following embodiments.
58, the fourth gear train IV, and the fifth friction clutch 65, respectively. In the following embodiments, the fifth gear 55,
A sixth gear 56, a third gear train III composed of these gears, and a fourth friction clutch 64 for connecting and disconnecting a power transmission path including the gear train are provided. The speeds correspond to the fifth speed and the sixth speed in the following embodiments, respectively, and in the following embodiments, the third speed and the fourth speed are separately provided.

As shown in FIG. 1, the automatic transmission 10 is a transmission case.
Inside 11 is a flywheel 2 on the engine output shaft 1 and a torsion spring 3 to soften the shock caused by rotational fluctuations during shifting.
An input shaft 20 whose front end is connected via a shock-absorbing disk 4 having a shaft, and a mounting drum 5 of a propeller shaft (not shown) arranged coaxially behind the input shaft 20 and at the rear end. The combined output shaft 30, the countershaft 40 arranged parallel to these shafts 20,30 and these shafts 20,3
A plurality of gear trains for transmitting and shutting off power between 0 and 40, a friction clutch, a one-way clutch, and the like are arranged.

A first gear 51 is loosely fitted to an intermediate portion of the input shaft 20 and a second gear is constantly meshed with the gear 51.
52 is splined to the front of the counter shaft 40,
The gears 51 and 52 form a first gear train I. Then, on the input shaft 20, the shaft 20
A wet multi-plate type first friction clutch 61 for connecting and separating the first gear 51 and the first gear 51 is provided. This first friction clutch 61
Is a drum 61a spline-coupled to the input shaft 20, a hub 61b integrally formed with the first gear 51,
A plurality of friction plates 61c disposed between the two and alternately spline-coupled to the drum 61a and the hub 61b, and the drums 61a and the hub 61b, in other words, by fastening these friction plates 61c when the operating pressure is introduced. For example, input shaft 20 and first gear 51
It is composed of a piston 61d for coupling and.

A third gear 53 is fitted to the rear end portion of the input shaft 20 via a first one-way clutch 71, and a fourth gear 54 that is constantly meshed with the gear 53 is loosely fitted to the counter shaft 40. The gears 53, 54 form a second gear train II. A second friction clutch 62 that connects and disconnects the shaft 40 and the fourth gear 54 is provided on the counter shaft 40. This clutch 62 is also drum 62a spline-connected to the counter shaft 40. And a hub 62b connected to the sleeve-like extension 54a of the fourth gear 54, a plurality of friction plates 62c arranged between the drum 62a and the hub 62b, and friction between these when the working pressure is introduced. The plate 62c is fastened to the drum 62a and the hub 62b, that is, the piston 62d for connecting the counter shaft 40 and the fourth gear 54.

Further, the first portion at the rear end of the input shaft 20
A third friction clutch 63 is arranged between the one-way clutch 71 and the front end portion of the output shaft 30. The clutch 63 also includes a drum 63a splined to the output shaft 30 and the first one-way clutch 71.
Outer race 71a (third gear 53) of the integral hub 63b,
A plurality of friction plates 63c arranged between the two are fastened to each other when the operating pressure is introduced and the hub 63b and the drum
It is composed of a piston 63d that connects with 63a. The third friction clutch 63 is engaged and the first friction clutch
The input shaft 20 and the output shaft 30 are coupled to each other when the one-way clutch 71 is locked. An engine brake friction clutch 66 is provided on the input shaft 20 in parallel with the first one-way clutch 71. The clutch 66 includes a drum 66a spline-coupled to the input shaft 20, a hub 66b integral with the outer race 71a of the first one-way clutch 71, a plurality of friction plates 66c arranged between them, and friction between them. It is composed of a piston 66d that fastens a plate 66c and connects the drum 66a and the hub 66b. Therefore, when the friction clutch 66 is engaged, the input shaft 20 and the hub 63b of the third gear 53 or the third friction clutch 63 are coupled even if the first one-way clutch 71 is free. Become.

On the other hand, a fifth gear 55 is integrally formed on the rear portion of the counter shaft 40, and a sixth gear 55 is always meshed with the fifth gear 55.
The gear 56 is loosely fitted to the output shaft 30, and the fifth and sixth gears 55 and 56 form a third gear train III. Then, immediately after the third friction clutch 6 on the output shaft 30, the shaft 30 and the sixth friction clutch 6 are provided.
A fourth friction clutch 64 for connecting and disconnecting the gear 56 is provided. This clutch 64 is an output shaft.
A drum 64a that is spline-coupled to the drum 30 and is integrated with the drum 63a of the third friction clutch 63, a hub 64b that is integrally formed with the sixth gear 56, and is disposed between the drum 64a and the hub 64b. The plurality of friction plates 64c that are connected to each other are fastened to each other when the operating pressure is introduced, and the drum 64a and the hub 64 are
b, that is, a piston 64d that connects the output shaft 30 and the sixth gear 56.

Further, a seventh gear 57 is provided at the rear end of the counter shaft 40.
Is spline-fitted, and an eighth gear 58, which normally meshes with the gear 57, is loosely fitted in the intermediate portion of the output shaft 30. These gears 57, 58 form a fourth gear train IV. . A second one-way clutch 72 and a fifth friction clutch 65 that connects and disconnects the shaft 30 and the eighth gear 58 are arranged in series on the output shaft 30 along the power transmission direction. The fifth friction clutch 65 includes a drum 65a splined to the output shaft 30 and a plurality of friction plates between the drum 65a.
The hub 65b is provided with a 65c, and a piston 65d for connecting the drum 65a and the hub 65b by fastening the friction plate 65c when the operating pressure is introduced. The hub 65d is a second one-way clutch. The one-way clutch 72 and the outer race 72b are integrated with the 72 inner race 72a and the eighth race described above.
It is integrally formed with the gear 58. Therefore, the eighth gear 58 is coupled to the output shaft 30 when the fifth friction clutch 65 is engaged and the second one-way clutch 72 is locked. An engine brake friction clutch 67 is concentrically provided inside the fifth friction clutch 65. The friction clutch 67 includes a drum 67a that is integral with the inner race 72a of the second one-way clutch 72 (hub 65b of the fifth friction clutch 65), a hub 67b integral with the outer race 72b (eighth gear 58), and the like. A plurality of friction plates 67c arranged between them and the friction plates 67c are fastened to each other, and the drum 67a and the hub 67b, that is, the second one-way clutch 72.
The inner race 72a and the outer race 72b are joined together by a piston 67d. Therefore, by engaging the engine brake friction clutch 67 and the fifth friction clutch 65, the eighth gear 58 and the output shaft 30 are connected even when the second one-way clutch 72 is in the free state.

Here, the first one-way clutch 71 locks when the rotation speed of the input shaft (inner race) 20 becomes higher than the rotation speed of the outer race 71a in the predetermined rotation direction to lock the rotation of the input shaft 20 to the outer race 71a. When the rotational speed of the outer race 71a exceeds the rotational speed of the input shaft 20, the outer race 71a will idle. Also, the second one-way clutch 72
Is locked when the rotation speed of the outer race 72b is about to become higher than the rotation speed of the inner race 72a with respect to the predetermined rotation direction, and the rotation is transmitted from the outer race 72b to the inner race 72a. It has become.

The first gear train I has a gear ratio of about 1, the second gear train II is decelerated when the rotation is transmitted from the third gear 53 to the fourth gear 54, and the third gear train III is the fifth gear. 55 to 6th gear 5
When the rotation transmission to 6 is performed, the fourth gear train IV is reduced at a reduction ratio even greater than that of the third gear train III when the rotation is transmitted from the seventh gear 57 to the eighth gear 58. The diameter is set from 51 to 58.

In addition to the above configuration, a reverse speed gear train V is provided between the counter shaft 40 and the output shaft 30. The gear train V is loosely fitted on a drive gear 81 integrally formed with the counter shaft 40, an idle gear 83 on an idle shaft 82 that is always meshed with the gear 81, and an output shaft 30 that is constantly meshed with the gear 83. Combined driven gear
It is composed of 84 and. And output shaft
A spline 85 is formed on the 30 and a spline 84 of the same shape is formed on the side surface of the driven gear 84 adjacent to the spline 85.
When the sleeve 86 that is formed with a and is slidably fitted to the former spline 85 is fitted over both splines 85 and 84a by the shift fork 87, the driven gear 84 is coupled to the output shaft 30. It is like this.

Further, in this embodiment, the parking gear 91 is fixedly installed on the outer periphery of the drum 65a of the fifth friction clutch 65, and
When the parking pole 92 is engaged with 1, the drum 65a
The output shaft 30 is fixed via the.

Further, the fourth gear 54 of the counter shaft 40 has a shaft 93
The power take-off gear 94 supported by the
It is designed to extract power used for various work other than vehicle driving.

Next, the power transmission state at each shift speed of the automatic transmission will be described with reference to the clutch operation table of Table 1 and the skeleton diagrams of FIGS. Here, in Table 1, the mark ◯ indicates the engaged state for the friction clutch and the locked state for the one-way clutch. Further, the mark (○) indicates the state of being engaged, but not involved in power transmission.

First, in the first speed, as shown in Table 1, the second friction clutch 62 and the fifth friction clutch 65 are engaged, and
The second one-way clutches 71, 72 are both locked. At this time, the output rotation of the engine is transmitted from the input shaft 20 to the third gear 53 of the second gear train II via the first one-way clutch 71, and further to the fourth gear, as shown by the inclined portion in FIG. Input from 54 to the counter shaft 40 via the second friction clutch 62. Then, the 7th and 8th gears 5 which further constitute the fourth gear train IV from the counter shaft 40
It reaches the output shaft 30 through 7,58, the second one-way clutch 72 and the fifth friction clutch 65. In this case, the rotation of the input shaft 20 is decelerated by the second gear train II and input to the counter shaft 40, and further reduced from the counter shaft 40 by the fourth gear train IV and transmitted to the output shaft 30. Since the reduction ratios of both the second and fourth gear trains are larger than those of the other gear trains, the first speed state having the largest reduction ratio can be obtained.

Next, when shifting from the first speed to the second speed, as shown in Table 1, the first friction clutch 61 is newly engaged in the above-described first speed state. At this time, as shown in FIG. 3, the rotation of the input shaft 20 is changed from the first friction clutch 61 to the first friction clutch 61.
It is input to the counter shaft 40 via the first and second gears 51 and 52 that form the gear train I, and the counter shaft
From 40, as in the case of the 1st speed, the 7th and 8th gears of the 4th gear train IV
Power is transmitted to the output shaft 30 via the gears 57, 58, the second one-way clutch 72 and the fifth friction clutch 65. That is, in this case, the power transmission from the input shaft 20 to the counter shaft 40 is performed via the first gear train I instead of the second gear train II at the first speed. The reduction ratio of I is approximately 1, and 1
Since it is smaller than the speed reduction ratio of the second gear train II that transmits power at high speed, a second speed state in which the speed reduction ratio is smaller than the first speed is obtained.

The shift from the first speed to the second speed is performed only by the engaging operation of the first friction clutch 61 as described above, and the second friction clutch 62 that was engaged at the first speed is in the engaged state.
Therefore, as shown by the dotted line in FIG.
The rotation transmitted to 40 is transmitted from the second friction clutch 62 to the fourth gear.
54 to the third gear 53, but in this case, the first one-way clutch 71 between the third gear 53 and the input shaft 20 is idling because the outer race 71a side rotates at high speed. Therefore, power is not transmitted from the input shaft 20 to the counter shaft 40 via the second gear train II.

Further, when shifting from the second speed to the third speed, as shown in Table 1, the first friction clutch 61 is released and the fourth friction clutch 64 is newly engaged from the second speed state. As a result, the fourth
As shown in the figure, first rotate the input shaft 20
As in the case of the high speed, it is transmitted to the third gear 53 of the second gear train II via the first one-way clutch 71, further transmitted from the fourth gear 54 to the counter shaft 40 via the second friction clutch 62, and From the counter shaft 40 to the third gear train II
5th and 6th gears 55 and 56 in I, and a 4th friction clutch 64
Is transmitted to the output shaft 30 via. In this case, the total reduction ratio of the second gear train II and the third gear train III is the first gear train I and the fourth gear train that transmit power at the second speed.
Since it is smaller than the total reduction ratio with IV, it is possible to obtain the state of the third speed, which is smaller than the second speed. In the third speed, the rotation of the counter shaft 40 is transmitted to the outer race 72b of the second one-way clutch 72 via the fourth gear train IV and the output shaft 30 as shown by the dotted lines in FIG. Is transmitted to the inner race 72a of the second one-way clutch 72 through the fifth friction clutch 65 in the engaged state. However, since the inner race 72a rotates at a higher speed than the outer race 72b, the second one-way clutch is rotated. 72 becomes idle and therefore counter shaft
There is no interference between the rotation of 40 and the rotation of the output shaft 30.

Further, when shifting from the third speed to the fourth speed, as shown in Table 1, the first friction clutch 61 is further engaged with respect to the third speed state. Therefore, the rotation of the input shaft 20 is changed from the first friction clutch 61 to the first friction clutch 61 as shown in FIG.
It is transmitted to the counter shaft 40 via the first and second gears 51 and 52 of the gear train I, and from the shaft 40 to the third gear train.
It is transmitted to the output shaft 30 via the fifth and sixth gears 55 and 56 of III and the fourth friction clutch 64. That is, in this case, the rotation transmission from the input shaft 20 to the counter shaft 40 is performed through the first gear train I having a reduction ratio smaller than that of the second gear train II in the third speed, instead of the second gear train II. Therefore, the fourth speed state in which the reduction ratio is smaller than the third speed is obtained. Incidentally, in the fourth speed, the second friction clutch 62 and the fifth friction clutch 65 are in the engaged state, but the first one-way clutch 71 has the same reason as in the second speed, and the second one-way clutch 72 is the same. For the same reason as in the case of the 3rd speed, the engine is idling, so that power is not transmitted via these clutches 71 and 72. Further, the second friction clutch 62 is released at an appropriate time after shifting to the fourth speed.

Next, at the time of shifting from the fourth speed to the fifth speed, as shown in Table 1, the third friction clutch 63 is newly engaged and the fourth friction clutch 64 is released from the state of the fourth speed. The rotation of the input shaft 20 is transmitted from the first one-way clutch 71 to the output shaft 30 via the third friction clutch 63 as shown in FIG. In this case, since none of the gear trains passes through, the rotation of the input shaft 20 is directly transmitted to the output shaft 30 to obtain the so-called direct-coupled fifth speed. In the fifth speed, the first friction clutch 61 and the fifth friction clutch 65 are in the engaged state, but the second one-way clutch 72 idles for the same reason as in the third and fourth speeds. The rotation transmitted from the shaft 20 to the counter shaft 40 via the first friction clutch 61 and the first gear train I does not interfere with the rotation of the output shaft 30.

Further, when shifting from the fifth speed to the sixth speed, as shown in Table 1, the second friction clutch 62 is engaged in addition to the state of the fifth speed. As a result, the rotation of the input shaft 20 is
As shown in the figure, it is transmitted from the first friction clutch 61 to the countershaft 40 via the first and second gears 51 and 52 of the first gear train I, and further from the second friction clutch 62 to the second gear train II of the second gear train II. Four,
It is transmitted to the output shaft 30 via the third gears 54, 53 and the third friction clutch 63. In this case, the power transmission from the counter shaft 40 to the output shaft 30 is the second.
The rotation speed is increased by transmitting the rotation from the fourth gear 54 having a large diameter to the third gear 53 having a small diameter in the gear train II at this time. Become. As a result, the so-called overdrive 6th speed is obtained. It should be noted that in the sixth speed, the second one-way clutch 72 is in the idling state.

As described above, the four gear trains I to IV arranged in parallel between the two parallel shafts are selectively brought into the power transmission state by the operation of the five friction clutches 61 to 65 and the two one-way clutches 71 and 72. As a result, six forward gears can be obtained. Then, each shift of 1-2, 3-4,5-6 is performed only by the operation of one friction clutch, and 2-3, 4
The gear shift of -5 is performed only by operating the two friction clutches.

The first one-way clutch 71 is locked in the first speed, the third speed, and the fifth speed, and the second one-way clutch 72 is locked in the first speed and the second speed to transmit power, respectively. During coasting of a vehicle in which driving force is input from the side, these one-way clutches 71, 72 run idle and the automatic transmission 1 enters a neutral state. Therefore, when the engine brake is applied during coasting, as shown in Table 1, the engine brake friction clutches 66 and 67 arranged in parallel with the first and second one-way clutches 71 and 72 are engaged, Power is transmitted instead of the corresponding one-way clutch. Therefore, in this case as well, the predetermined shift speed is obtained and the engine brake is operated.

At the reverse speed, the first friction clutch 61 is engaged and the first one-way clutch 71 is locked (or the engine brake friction clutch 66 is engaged), and the driven gear 84 of the reverse speed gear train V is sleeve 86. Is coupled to the output shaft 30 via. Therefore, the rotation of the input shaft 20 passes through the first one-way clutch 71 (or the friction clutch 66 for engine braking), the second gear train II, the second friction clutch 62, the counter shaft 40 and the gear train V for reverse speed and the output shaft 30. However, since the reverse speed gear train V is provided with the idle gear 83, the rotation direction of the output shaft 30 is reversed.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view showing the overall structure of an automatic transmission, and FIGS. 2 to 7 are skeleton diagrams of gear trains showing power transmission paths of respective gears. 10 …… Automatic transmission, 20 …… Input shaft, 30 ……
Output shaft, 40 …… Counter shaft, 51〜
58 …… Gear, 61-65 …… Frictional clutch, 71,72 …… One-way clutch.

Claims (1)

[Claims] 1. An input shaft (20), an output shaft (30) arranged coaxially behind the input shaft, a counter shaft (40) arranged parallel to these shafts, and an input shaft (30). First friction clutch (61) that connects and disconnects the power transmission path consisting of the first gear (51) of the second gear and the second gear (52) on the counter shaft that meshes with the first gear, and an input at the rear end of the input shaft. The third gear (53) provided via the first one-way clutch (71) that allows the rotation transmission from the side to the output side, and the fourth gear (54) on the counter shaft that meshes with the third gear (53). And a second friction clutch (62) for connecting and disconnecting the power transmission path, which is provided at the front end portion of the output shaft, and is connected to the input shaft via the first one-way clutch. The third that connects and disconnects the power transmission path to the output shaft
The friction clutch (63), the fifth gear (57) at the rear end of the counter shaft, the sixth gear (58) on the output shaft that meshes with the fifth gear, and the rotation transmission from the input side to the output side are allowed. And a fourth friction clutch (65) for connecting and disconnecting a power transmission path including a second one-way clutch (72).