JP2671461B2 - Gearbox for automatic transmission - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear transmission used in an automatic transmission for vehicles, and more particularly to a gear transmission formed by combining three sets of planetary gears.

As is well known in the prior art, a planetary gear has three elements, a sun gear, a ring gear, and a carrier that holds a pinion gear that meshes with the sun gear, and any one of those elements serves as an input element and one of the other elements serves as an output element. By fixing other remaining elements, it is possible to accelerate the input rotation, decelerate in the normal rotation, or decelerate in the reverse direction and output it. Therefore, conventionally, in general, a plurality of planetary gears are combined. Form a gear transmission for an automatic transmission. In that case, depending on how to combine the planetary gears, the value of the gear ratio of the planetary gears (the ratio of the number of teeth of the sun gear and the ring gear), and whether to use a single pinion type planetary gear or a double pinion type planetary gear, Although the obtained gear ratios vary in various ways, not all combinations are practical, but the possibility of practical use depends on various conditions such as vehicle mountability, manufacturing possibility, gear shifting characteristics, and required power performance. Gear trains with are limited. In other words, the planetary gear train can be configured in a huge number depending on the combination of planetary gears and the setting of the gear ratio, so that it satisfies various conditions required for an automatic transmission for a vehicle. There are many difficulties involved in creating.

Conventionally, a large number of gear transmissions devised under such a background have been proposed. Among them, a device using three sets of planetary gears is disclosed in, for example, JP-A-51-17767 and 61-4.
8062, 51-108168, 51-108170, and 51-127968.

DISCLOSURE OF INVENTION Problems to be Solved by the Invention However, in a gear transmission in which a plurality of sets of planetary gears are combined, how to connect each planetary gear, which element is connected to the input shaft, or which element is fixed The number of gears that can be set and the gear ratio at each gear change in various ways depending on whether or not. Therefore, in practical use, the gear transmission is selected based on the relationship with the engine output, the application of the vehicle in which it is mounted, the required characteristics, and the like. In that case, not only the arrangement of clutches and brakes,
Even if the structure of the gear train is different from the existing gear transmission, not only the number of gear transmissions to be prepared will increase to the same extent as the type of vehicle, but also the design and manufacturing will be included. The productivity of the gear transmission will be deteriorated, and the basic design will be redone for each gear transmission having different specifications, and the productivity will be deteriorated because the production process cannot be shared.

On the other hand, as described above, in a gear transmission in which a plurality of sets of planetary gears are combined, the gear ratio that can be set greatly changes depending on the connection of each element and the arrangement of clutches and brakes. The number of clutches for input and the number of brakes for fixing the elements is fixed in the gear train of such a configuration by making the method of connecting the elements of No. 1 constant regardless of whether they are always connected or connected via a clutch. It is technically possible to appropriately determine the number of gears that can be set and the gear ratio thereof depending on the arrangement of the gears and the arrangement. It is considered that the above problems can be solved to some extent by standardizing the above. In that case, the basic structure of the gear train is that it is compact and lightweight as a whole, that it is easy to manufacture, that the gear ratio that can be set is close to a geometric series, and that it is advantageous in reducing gear shock. It is preferable to satisfy the requirements that a gear ratio of "1" or less can be set as necessary, and that the maximum gear ratio and the minimum gear ratio are wide.

Considering the conventional gear transmission described above from the viewpoint of obtaining such a so-called gear train having a wide diversion possibility, any of the conventional gear transmissions described above has a so-called overdrive stage in which the gear ratio is "1" or less. It is not supposed to be able to set, and there is no description of how to change the arrangement of clutches and brakes in order to change the shift speed that can be set,
Further, it is considered that the gear ratio does not always have a relationship close to a geometric series, and special consideration is required for reducing gear shift shock, or it is difficult to drive.

The present invention has been made in view of the above circumstances,
An object of the present invention is to provide a gear transmission for an automatic transmission including a basic configuration that can be easily changed to various specifications and that can satisfy a variety of combined conditions.

Means for Solving the Problems The present invention includes three sets of single pinion type planetary gears each having a sun gear, a ring gear, and a carrier that holds a pinion gear that meshes with the sun gear and the ring gear. Carrier and second
Of the planetary gear and the ring gear of the third planetary gear are always connected or selectively connected via an engaging means, and the sun gear of the first planetary gear and the ring gear of the second planetary gear are connected. And are always connected or selectively connected through the engagement means,
Further, the sun gear in the second planetary gear and the sun gear in the third planetary gear are always connected or selectively connected via an engaging means.

In the device of the present invention, the carrier of the first planetary gear, the carrier of the second planetary gear, and the ring gear of the third planetary gear, which are connected to each other, are integrated with each other, or individually, or with the sun gear of the first planetary gear. A ring gear of the second planetary gear integrally or individually, or a sun gear of the second planetary gear and a sun gear of the third planetary gear integrally or individually, and also as an independent element The ring gear of the planetary gear, the carrier of the third planetary gear, and the like are each an input element, an output element, or a fixed element. As a result, the planetary gears integrally or independently perform acceleration / deceleration actions to change the speed of the rotation of the input shaft, or as it is, or reversely, and transmit it to the output shaft. The gears in that case are set to, for example, five forward gears and one reverse gear, or lower gears, and the range between the largest gear ratio and the smallest gear ratio is wide. The values are close to a geometric series.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view showing the principle of one embodiment of the present invention. The gear transmissions shown here are respectively arranged in a sun gear, a ring gear, and the sun gear and the ring gear, and mesh with each other. Each of the elements of the three sets of single pinion type planetary gears 1, 2 and 3 having a carrier that holds a pinion gear is connected as follows.

That is, the carrier 1C of the first planetary gear 1 is integrally connected to the carrier 2C of the second planetary gear 2, and
These carriers 1C, 2C are selectively connected to the ring gear 3R of the third planetary gear 3 via the third clutch means K3. The sun gear of the first planetary gear 1
1S is integrally connected to the ring gear 2R of the second planetary gear 2, and the sun gear 2S of the second planetary gear 2 and the sun gear 3S of the third planetary gear 3 are also integrally connected.

In addition, as a connection structure of the above-described components, a connection structure employed in a general automatic transmission such as a hollow shaft, a solid shaft, or an appropriate connecting drum can be employed.

The input shaft 4 is connected to an engine (not shown) via a power transmission means (not shown) such as a torque converter or a fluid break, and the input shaft 4 and the sun gear 1S of the first planetary gear 1 and A first clutch means K1 is provided between the second planetary gear 2 and the ring gear 2R for selectively connecting them, and the input shaft 4 and the ring gear 1R of the first planetary gear 1 are connected to each other.
Second clutch means for selectively connecting the two
K2 is provided. These clutch means K1, K2, K3
The purpose is to selectively connect and disconnect the above-mentioned members, and to engage / disengage them by a mechanism such as a hydraulic servo mechanism adopted in a general automatic transmission in the past. Wet multi-disc clutch, one-way clutch,
Alternatively, a configuration in which the wet multi-plate clutch and the one-way clutch are arranged in series or in parallel can be adopted as necessary. It should be noted that in practical use, there are restrictions on the arrangement of each component, so that each clutch means K1, K
It goes without saying that an appropriate intermediate member such as a connecting drum can be interposed as a connecting member for 2, K3.

Further, the first brake means B1 for selectively preventing the rotation of the ring gear 1R of the first planetary gear 1 includes the ring gear 1R and a transmission case (hereinafter simply referred to as a case) 6
It is provided between and. Second brake means B2 for selectively preventing rotation of the carrier 3C of the third planetary gear 3 is provided between the carrier 3C and the case 6. Further, third brake means B3 for selectively preventing rotation of the sun gear 2S of the second planetary gear 2 and the sun gear 3S of the third planetary gear 3 connected to each other is provided between the sun gears 2S, 3S and the case 6. It is provided. These braking means B
1, B2, B3 should be a wet multi-plate brake or band brake driven by a hydraulic servo mechanism that has been adopted in conventional automatic transmissions, a one-way clutch, or a combination of these. In practical use, an appropriate connecting member is interposed between these braking means B1, B2, B3 and each element to be fixed by these braking means B1, B2, B3 or between the case 6. Of course you can get it.

The output shaft 5 that transmits the rotation to the propeller shaft and the counter gear (not shown) is the third planetary gear 3
Is connected to the ring gear 3R.

The gear transmission configured as described above is capable of shifting gears in five forward gears and one reverse gear, and each of these gears has the above-mentioned clutch means K1, K2, K3 and brake means B.
This is accomplished by engaging 1, B2, B3 as shown in Table 1. It should be noted that Table 1 also shows the gear ratios of the respective shift speeds and the specific values thereof. The specific values are the gear ratios ρ1, ρ2, ρ3 of the planetary gears 1, 2, 3 and ρ1 = 0.400. , Ρ2 =
It is a value when 0.379 and ρ3 = 0.471. Further, in Table 1, the mark “◯” indicates the engaged state, and the blank indicates the released state. Hereinafter, each shift speed will be described.

<< First Forward Speed >> The first clutch means K1, the third clutch means K3, and the first brake means B1 are engaged. That is, the sun gear 1S of the first planetary gear 1 and the ring gear of the second planetary gear 2.
2R is connected to the input shaft 4, while the ring gear 1R of the first planetary gear 1 is fixed. Therefore, in the first planetary gear 1, the sun gear 1S rotates together with the input shaft 4 in a state where the ring gear 1R is fixed, so that the carrier 1C is decelerated with respect to the input shaft 4 to rotate forward (rotate in the same direction as the input shaft 4). .same as below)
Then, this is transmitted to the carrier 2C of the second planetary gear 2, and is also transmitted to the ring gear 3R of the third planetary gear 3 and the output shaft 5 via the third clutch means K3. That is, the input shaft 4
Is reduced by the first planetary gear 1 and transmitted to the output shaft 5. The second planetary gears 2 and the third planetary gears 3 do not perform the acceleration / deceleration action because the sun gears 2S and 3S are not connected to the case 6. Therefore, the gear ratio in this case is represented by (1 + ρ ₁ ) / ρ ₁ as shown in Table ₁ , and its specific value is 3.500.

<< Second Forward Speed >> The first clutch means K1, the third clutch means K3, and the second brake means B2 are engaged. That is, in the first forward speed state, the second brake means B2 is engaged instead of the first brake means B1. In this case, since the ring gear 1R is not connected to the input shaft 4 and the case 6 in the first planetary gear 1, no particular acceleration / deceleration action is performed. On the other hand, in the second planetary gear 2, since the load from the output shaft 5 is applied to the carrier 2C, the ring gear 2R rotates together with the input shaft 4 so that the sun gear 2S rotates in the reverse direction (opposite to the input shaft 4). Direction rotation. The same applies below), and this sun gear
2S and the sun gear S3 of the third planetary gear 3 rotate integrally. Therefore, in the third planetary gear 3, since the sun gear 3S rotates in the reverse direction with the carrier 3C fixed, the ring gear 3R
And the carrier 2C of the second planetary gear 2 connected to this
The output shaft 5 and the output shaft 5 are decelerated with respect to the input shaft 4 and rotate in the normal direction. Therefore, in this case, the second planetary gear 2 and the third planetary gear 3 perform a deceleration action, and the speed change ratio thereof is represented by {ρ ₃ + ρ ₂ (1 + ρ ₃ )} / ρ _{3 as shown} in Table 1. The specific value is 2.184.

<< Forward Third Speed >> The first clutch means K1 and the third clutch means K3 are engaged, and the third brake means B3 is engaged, as in the case of the first speed and the second speed. That is, in the state of the second speed, the third brake means B3 is engaged instead of the second brake means B2. In this case, the ring gear 1R of the first planetary gear 1 is not connected to the input shaft 4 and the case 6 as in the case of the second forward speed, and no particular acceleration / deceleration is performed, and the third planetary gear 3 However, the carrier 3C is not connected to the case 6 and no particular acceleration / deceleration action is performed. On the other hand, in the second planetary gear 2, the ring gear 2R rotates together with the input shaft 4 with the sun gear 2S fixed, so that the carrier 2C
Is decelerated with respect to the input shaft 4 and rotates in the normal direction, and this is transmitted to the output shaft 5. That is, the rotation of the input shaft 4 is reduced only by the second planetary gear 2 and transmitted to the output shaft 5, and the gear ratio thereof is represented by 1 + ρ ₂ as shown in Table 1, and its specific value is 1.379. Become.

<< Fourth forward speed >> Engage the first to third clutch means K1, K2, K3,
And release all braking means B1, B2, B3. That is, in the state of the third speed, the second clutch means K2 is engaged instead of the third brake means B3. Therefore, since the sun gear 1S and the ring gear 1R are connected to the input shaft 4 in the first planetary gear 1, the whole thereof rotates together with the input shaft 4 and, as a result, the carrier of the first planetary gear 1 The output shaft 5 connected to 1C via the third clutch means K3 is the input shaft 4
Rotates at a constant speed. In this case, the second planetary gear 2
Has its carrier 2C connected to the carrier 1C of the first planetary gear 1 to rotate at the same speed as the input shaft 4 and the ring gear 2R to rotate integrally with the input shaft 4, so that the whole of the input shaft 4 and the input shaft 4 Rotate at a constant speed. The third planetary gear 3
The sun gear 3S is connected to the sun gear 2S of the second planetary gear 2, rotates at the same speed as the input shaft 4, and the ring gear 3R
Is connected to the carrier 2C of the second planetary gear 2 and rotates at the same speed as the input shaft 4, so that the whole unit rotates at the same speed as the input shaft 4. Eventually, the entire gear train rotates together with the input shaft 4, so that the acceleration / deceleration action does not occur and the reduction ratio becomes "1".

<< Fifth forward speed >> Second clutch means K2, third clutch means K3 and third
Engage with the braking means B3. That is, the above-mentioned fourth
In the high speed state, the third brake means B3 is engaged instead of the first clutch means K1. In this case, in the first planetary gear 1, the sun gear 1S and the carrier 1C rotate normally due to the ring gear 1R rotating together with the input shaft 4, but the rotation of the carrier 1C is transmitted to the carrier 2C of the second planetary gear 2. as a result,
In the second planetary gear 2, the carrier 2C rotates normally while the sun gear 2S is fixed, so that the ring gear 2R rotates faster than the carrier 2C and is transmitted to the sun gear 1S of the first planetary gear 1. Therefore, in the first planetary gear 1, the ring gear 1R rotates together with the input shaft 4 while the sun gear 1S is positively rotating at high speed. Therefore, the carrier 1C, that is, the output shaft 5 is faster than the input shaft 4 and It rotates forward at a slower speed than the sun gear 1S of the planetary gear 1. The third planetary gear 3
Does not perform any acceleration / deceleration action because the carrier 3C is not connected to the case 6. Eventually, the rotation of the input shaft 4 is increased in speed by the first planetary gear 1 and the second planetary gear 2 and transmitted to the output shaft 5, and the speed ratio thereof is the first.
As shown in the table, it is expressed as 1-ρ ₁ ρ ₂ , and its specific value is 0.848.

<< Reverse >> The first and second clutch means K1, K2 and the second brake means B2 are engaged. That is, the sun gear 1S and the ring gear 1R of the first planetary gear 1 and the ring gear 2R of the second planetary gear 2 are connected to the input shaft 4, and the carrier 3C of the third planetary gear 3 is fixed. Therefore, since the sun gear 1S and the ring gear 1R rotate together with the input shaft 4, the first planetary gear 1 is integrally rotated as a whole at the same speed as the input shaft 4, and the second planetary gear 2 also has its ring gear. While 2R is connected to the input shaft 4, the carrier 2C is connected to the carrier 1C of the first planetary gear 1 and rotates at the same speed as the input shaft 4, so that the entire unit is integrated with the input shaft 4. Rotate forward at speed. On the other hand, in the third planetary gear 3, since the sun gear 3S is connected to the sun gear 2S of the second planetary gear 2 and rotates normally at the same speed as the input shaft 4, and the carrier 3C is fixed, the ring gear 3R is fixed. And the output shaft 5 connected to this rotates in the reverse direction. Therefore, the rotation of the input shaft 4 is substantially inverted and decelerated by only the third planetary gear 3 and transmitted to the output shaft 5 to be in the reverse stage. The gear ratio is represented by −1 / ρ ₃ as shown in Table 1, and its specific value is −2.123.

As is clear from the above description of each shift stage, in the gear transmission shown in FIG. 1, the gear ratio of each shift stage from the first speed to the fourth speed is close to a geometric series. The ratio of the engine speeds before and after the gear shift is substantially constant, and the automatic transmission can be operated easily. Furthermore, since the gear ratio of the overdrive stage is approximately 0.848, which is an appropriate value within the practical range, the engine speed during high-speed running can be reduced while maintaining power performance, and fuel efficiency and quietness can be improved. Can be one. Then, as described in the description of each shift speed, when shifting to another adjacent shift speed, it suffices to release any one of the engagement means and engage the other engagement means, that is, Since shifting can be performed by switching the individual engaging means, shift control is easy and shift shock can be reduced. On the other hand, in the above gear transmission, the planetary gears may be three sets, and
The planetary gears 1, 2, and 3 may have a well-balanced gear ratio of about 0.38 to 0.47 so that the planetary gears do not increase in diameter and the second planetary gears are not increased. 2 sun gear 2S and 3rd planetary gear 3 sun gear
It is possible to make the 3S and the long pinion, and therefore, according to the above-mentioned gear transmission, the overall configuration can be simplified and the size can be reduced. In addition, the relative rotation speed of the pinion gears of the planetary gears 1, 2 and 3 with respect to the carriers 1C, 2C and 3C is lowered, and the durability of the bearings can be improved.

By the way, as is known from Table 1, each planetary gear 1,2,
3 does not perform the acceleration / deceleration action at all gears, but an appropriate planetary gear performs the acceleration / deceleration action according to the engagement / disengagement state of the clutch means and the brake means.
Therefore, the basic connection relationship (connection relationship described in the section of means for solving the problem) of each element in each planetary gear 1, 2, 3 is not achieved by, for example, continuous connection by a connecting drum, and Even if the configuration is achieved by the clutch means such as the third clutch means K3, the required shift speed can be obtained.

FIG. 2 shows an example thereof, and in the configuration of FIG. 1 described above, a fourth clutch means for selectively connecting the sun gear 2S and the ring gear 2R in the second planetary gear 2 to each other.
It is through K4. The operation table of the gear transmission having the configuration shown in FIG. 2 is as shown in Table 2. Even with the configuration shown in FIG. 2, setting of 5 forward gears and 1 reverse gear is required. You can

By the way, in the above-mentioned respective embodiments, the respective clutch means K1, K
2, K3, K4 are shown by the symbol of the multi-disc clutch, but in the present invention, a one-way clutch other than the multi-disc clutch is used as the clutch means in order to improve quietness, fuel consumption, and mitigation of shift shock. Alternatively, it is possible to use a configuration in which a multi-disc clutch and a one-way clutch are combined, and for the braking means B1, B2, B3, in addition to the multi-disc brake shown in each of the above embodiments, one-way It is possible to use a clutch, a band brake, or a combination thereof. As a modification of such clutch means and brake means, Japanese Patent Application No. 176270/63 (Japanese Patent Application Laid-Open No. 26350) and Japanese Patent Application No. 63-221670 (Japanese Patent Application Laid-Open No. 2-221670) already filed by the present applicant. No. 72245 gazette) described in the specification and drawings attached to the application can be adopted.

Although the present invention has been described with reference to the first and second embodiments, it is needless to say that the present invention is not limited to the above-mentioned embodiments. It suffices to have the configuration described in the section "Means for solving".

As described above, according to the present invention, there is provided a gear transmission using three sets of single pinion type planetary gears, which is smaller and lighter in weight, reduces shift shock, and improves power performance of the vehicle. It is possible to obtain a gear transmission for an automatic transmission, which can satisfy practical requirements such as the above and whose specifications can be easily changed.

[Brief description of the drawings]

1 and 2 are skeleton diagrams showing the respective embodiments of the present invention. 1,2,3 …… Planetary gear, 1S, 2S, 3S …… Sun gear, 1C, 2C, 3C
...... Carrier, 1R, 2R, 3R …… Ring gear.

Claims (1)

(57) [Claims] 1. A single pinion type three sets of planetary gears each having a sun gear, a ring gear, and a carrier that holds a pinion gear that meshes with the sun gear and the ring gear. The carrier of the gear and the ring gear of the third planetary gear are always connected or selectively connected via the engagement means, and the sun gear and the second gear of the first planetary gear are connected.
Of the planetary gears are always connected or selectively connected through the engaging means, and the sun gear of the second planetary gear and the sun gear of the third planetary gear are always connected or through the engaging means. A gear transmission for an automatic transmission, characterized in that the transmission is selectively connected.