JP2629189B2 - 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 for an automatic transmission, and more particularly to a gear transmission mainly composed of a planetary gear mechanism.

2. Description of the Related Art As is well known, an automatic transmission for an automobile transmits an engine rotation to a gear transmission mainly including a planetary gear mechanism via a torque converter, and includes any one of three members constituting the planetary gear mechanism. By fixing the clutch with a clutch or a brake and using the other two members as an input member and an output member, the overall speed ratio is appropriately set. By the way, the number of shift stages that can be set in the automatic transmission is desirably as large as possible in view of demands such as improvement in power performance. For this purpose, it is conceivable to use a large number of planetary gear mechanisms. Conversely, from the demands of improved fuel efficiency, it is desirable that the structure be as simple as possible and light in weight. To that end, the number of planetary gear mechanisms used must be reduced, and clutches and brakes It is necessary to reduce the number of engaging members. Conventionally, as an automatic transmission for satisfying such conflicting requirements, for example, as described in JP-B-47-28822,
2. Description of the Related Art An automatic transmission mainly based on a Simpson-type compound planetary gear mechanism using two sets of single pinion type planetary gear mechanisms in parallel is known, which comprises a carrier of a first planetary gear mechanism and a carrier of a second planetary gear mechanism. A ring gear, a ring gear of the first planetary gear mechanism, and a carrier of the second planetary gear mechanism, each of which is connected to a sun gear of the first planetary gear mechanism, or a sun gear and the carrier, and a clutch for inputting to the sun gear of the second planetary gear mechanism; And a brake for selectively fixing each of a sun gear and a carrier of the first planetary gear mechanism. Further, an output shaft is connected to a carrier of the second planetary gear mechanism, and the third forward speed or the fourth forward speed and the first reverse speed are provided. It is configured to be able to set the shift speed of the vehicle.

Problems to be Solved by the Invention However, in the above-mentioned conventional automatic transmission, each gear is obtained by appropriately connecting and fixing predetermined elements in each planetary gear mechanism. In the case of each of the third gear and the reverse, the rotational force of the input shaft is transmitted to only one of the sun gears, and the diameter of the sun gear is relatively small.
As a result, there has been a problem that the allowable input torque is limited by the strength of the teeth in the sun gear, and the durability of the sun gear is reduced. It is conceivable to cope with such inconvenience by increasing the diameter of the sun gear, but doing so causes other problems such as an increase in the overall size of the gear transmission mechanism.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a gear transmission for an automatic transmission that has less restriction on allowable input torque and can improve durability. .

Means for Solving the Problems According to the present invention, in order to achieve the above object, in a Simpson-type compound planetary gear mechanism, at least four forward speeds and one reverse speed can be obtained by input from a ring gear and a carrier. And more specifically, a sun gear and a ring gear concentrically arranged with respect to the sun gear, and a planet pinion arranged between the sun gear and the ring gear and meshing with the sun gear and the ring gear. Are arranged coaxially, the sun gear of the first planetary gear mechanism and the sun gear of the second planetary gear mechanism are connected and integrated with each other, and the first planetary gear mechanism Selectively connect the carrier to the carrier or ring gear of the second planetary gear set, or release the connection. Latch means is provided, and other clutch means for selectively connecting the input shaft to the ring gear and the carrier in the first planetary gear mechanism are provided. Further, rotation of each sun gear and rotation of the carrier in the second planetary gear mechanism are provided. Are provided, and an output shaft is connected to a ring gear in the second planetary gear mechanism.

In the gear transmission according to the present invention, the input shaft is connected to the ring gear of the first planetary gear mechanism and the carrier of the first planetary gear mechanism is connected to the ring gear of the second planetary gear mechanism by the clutch means and the brake means. And the second
By preventing the rotation of the carrier of the planetary gear mechanism,
If the first forward speed with the largest gear ratio is achieved, and if the rotation of each sun gear is blocked instead of the rotation of the carrier in the second planetary gear mechanism, the second forward speed is achieved. In addition, if the input shaft is connected to the ring gear and the carrier of the first planetary gear mechanism and the respective carriers are connected to each other, the speed ratio at which the entire body rotates integrally becomes “3”, which is the third forward speed. Further, when the input shaft is connected to the carrier in the first planetary gear mechanism, the carriers are connected to each other, and the rotation of each sun gear is prevented, the forward speed becomes the fourth forward speed with the gear ratio of “1” or less. On the other hand, if the input shaft is connected to the ring gear and the carrier in the first planetary gear mechanism and the rotation of the carrier in the second planetary gear mechanism is prevented, the rotation of the input shaft is reversed and transmitted to the output shaft, and It becomes a step.

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

FIG. 1 is a schematic view showing the principle of an embodiment of the present invention. The gear transmission shown here is a Simpson-type composite in which two sets of single pinion type planetary gear mechanisms 1 and 2 are coaxially arranged. Each of these planetary gear mechanisms 1 and 2 is provided with sun gears 3 and 4 and ring gears 5 and 6 and between the sun gears 3 and 4 and the ring gears 5 and 6. Planet gears 7 and 8 mesh with sun gears 3 and 4 and ring gears 5 and 6 and carriers 9 and 10 holding these planet pinions 7 and 8 are provided. Among these planetary gear mechanisms 1 and 2, the sun gear 3 in the first planetary gear mechanism 1 and the sun gear 4 in the second planetary gear mechanism 2 on the right side of FIG. 1 are formed on, for example, a sun gear shaft, or attached to the sun gear shaft. As a result, they are connected so as to be integrated. A coupling clutch means C3 is provided between the carrier 9 in the first planetary gear mechanism 1 and the carrier 10 in the second planetary gear mechanism 2,
By engaging the clutch means C3, each carrier is
The carriers 9 and 10 are rotated independently by connecting the carriers 9 and 10 to each other so as to be integral with each other, and by releasing the connection. Further, another coupling means C4 for connection is provided between the carrier 9 of the first planetary gear mechanism 1 and the ring gear 6 of the second planetary gear mechanism 2, and the first planetary gear mechanism is provided by the clutch means C4. The first carrier 9 and the ring gear 6 of the second planetary gear mechanism 2 are selectively connected. This type of connection structure is commonly used in conventional automatic transmissions for vehicles, such as an intermediate shaft such as a hollow shaft or a solid shaft concentrically arranged with the planetary gear mechanisms 1 and 2, or a connection structure via an appropriate connecting drum. A configuration in which the members described above are interposed can be adopted.

The input shaft 11 is arranged on the same axis as the planetary gear mechanisms 1 and 2, and is connected to an engine (not shown) via a torque converter. An input clutch means C1 is provided between the input shaft 11 and the ring gear 5 of the first planetary gear mechanism 1, and the input shaft 11 and the first planetary gear mechanism 1 are provided.
Other clutch means for input to the carrier 9 at
C2 is provided.

The above-mentioned clutch means C3, C4 and the clutch means C1, C2 for inputting these are basically for selectively connecting and disconnecting the above-mentioned members, and are, for example, hydraulic servo mechanisms. Conventionally, a wet multi-plate clutch that is engaged and released by a mechanism generally employed in automatic transmissions, a one-way clutch, or a configuration in which these wet multi-plate clutches and one-way clutches are arranged in series or in parallel, etc. It can be adopted as needed. In practical use, there are restrictions on the arrangement of each component, so that each clutch means C1, C2, C3, C4 is directly connected to the carrier.
In some cases, it may not be possible to arrange them between the gears 9 and 10 and the ring gears 5 and 6, and in such a case, it is needless to say that an appropriate intermediate member such as a connecting drum is interposed.

The first brake means B1 for preventing rotation of the sun gears 3, 4 connected to each other is provided by the sun gear 3 (or 4).
And a transmission case (hereinafter simply referred to as a case) 12 and a second brake means B2 for preventing rotation of the carrier 10 in the second planetary gear mechanism 2.
Is provided between the case 12 and its carrier 10. These brake means B1 and B2 have a wet multi-plate brake or band brake driven by a hydraulic servo mechanism or the like generally used in an automatic transmission, or a one-way clutch, or a combination of these. And in practical use, these brake means B
1, B2 and sun gear 3,4 or carrier 10 or case 1
It goes without saying that an appropriate connecting member can be interposed between the second member and the second member.

Further, an output shaft 13 for transmitting rotation to a propeller shaft and a counter gear (each not shown) is connected to the ring gear 6 of the second planetary gear mechanism 2.

In the gear transmission configured as described above, four forward speeds and one reverse speed can be shifted, and each of these speeds is controlled by the clutch means C1, C2, C3, C4 and the brake means B1, This is achieved by engaging B2 as shown in Table 1. Table 1 also shows the gear ratios of the respective gears and their specific values. The specific values are the tooth ratios ρ1, ρ2 in the respective planetary gear mechanisms 1, 2, and ρ1 = 0.600, ρ2
= 0.428. In Table 1, a circle indicates an engaged state, and a blank indicates a released state. Hereinafter, each shift speed will be described.

<< First Forward Speed >> One input clutch means (hereinafter referred to as first clutch means) C1 and one coupling means (hereinafter referred to as fourth clutch means) C4 and second brake means B2 are provided. Engage. That is, input is made to the ring gear 5 of the first planetary gear mechanism 1, the carrier 9 of the first planetary gear mechanism 1 is connected to the ring gear 6 of the second planetary gear mechanism 2, and the carrier 10 of the second planetary gear mechanism 2 is Is fixed. Therefore, although there is no fixed element in the first planetary gear mechanism 1, the load of the output shaft 13 is applied to the carrier 9 of the first planetary gear mechanism 1, and the sun gear 3 is rotated in the opposite direction to the input shaft 11 to rotate ( On the other hand, in the second planetary gear mechanism 2, since the carrier 10 is fixed, the ring gear 6 is decelerated by the input of the reverse rotation direction from the sun gear 4 and is moved in the same direction as the input shaft. Attempts to rotate (forward rotation).
The first ring gear 6 has a first clutch means C4.
Since the carrier 9 of the planetary gear mechanism 1 is connected, the carrier 9 of the first planetary gear mechanism 1 eventually rotates forward. As a result, the rotation speed of the sun gear 3 of the first planetary gear mechanism 1 decreases Slower than when fixed. Ie input shaft
The rotation of 11 is speed-reversed in the first planetary gear mechanism 1 and transmitted to the second planetary gear mechanism 2 via the sun gears 3 and 4,
In addition, the speed is reduced in the second planetary gear mechanism 2 to be forward rotation, and the reduced rotation is given to the carrier 9 of the first planetary gear mechanism 1 to reduce the speed increasing action of the first planetary gear mechanism 1, As a result, power is circulated as a whole to perform a deceleration action, and the gear ratio is 1 + ρ1 + ρ1 / ρ2 as shown in Table 1.

<< Second forward speed >> The first clutch means C1, the fourth clutch means C4, and the first brake means B1 are engaged. That is, the carrier 9 of the first planetary gear mechanism 1 is connected to the ring gear 6 of the second planetary gear mechanism 2, and the sun gears 3, 4 are fixed and input to the ring gear 5 of the first planetary gear mechanism 1. Therefore, in the first planetary gear mechanism 1, the carrier 9 is decelerated and rotates forward because the sun gear 3 is fixed, and the rotation is performed by the second planetary gear mechanism 2 connected to the output shaft 13.
Is transmitted to the ring gear 6 of the first planetary gear mechanism 1, and as a result, only the first planetary gear mechanism 1 performs the shifting operation. As a result, the gear ratio is determined by the ratio of the number of teeth in the first planetary gear mechanism 1, and becomes 1 + ρ1. .

<< Third forward speed >> The first clutch means C1, another clutch means for input (hereinafter, referred to as second clutch means) C2, and another clutch means for connection (hereinafter, referred to as third clutch means) C3, Is engaged. That is, the carrier 9 in the first planetary gear mechanism 1
The input shaft 13 is connected to the ring gear 5 and the carrier 9 in the first planetary gear mechanism 1 while the and the carrier 10 in the second planetary gear mechanism 2 are connected. Therefore, in the first planetary gear mechanism 1, since the two members serve as input elements, the whole rotates integrally. In addition, in the second planetary gear mechanism 2, in addition to the carrier 10 serving as an input element, the sun gear 4 is connected to the sun gear 3 of the first planetary gear mechanism 1 and rotates at the same speed as the input shaft 11 in the same direction. Also, in the second planetary gear mechanism 2, the two members serve as input elements, and as a result, the entire second planetary gear mechanism 2 rotates integrally. That is, since the whole of the first planetary gear mechanism 1 and the second planetary gear mechanism 2 rotate integrally,
The gear ratio becomes "1".

<< Fourth forward speed >> The second and third clutch means C2, C3 and the first brake means B1 are engaged. That is, the carrier 9 and 10 are connected to each other, and the sun gears 3 and 4 are fixed and input to the carrier 9 in the first planetary gear mechanism 1. In this case, in the first planetary gear mechanism 1, the ring gear 5 only idles and does not particularly perform a shifting operation, whereas in the second planetary gear mechanism 2, the sun gear 4 is fixed to the carrier 10 from the carrier 10. As an input, the ring gear 6 is accelerated and rotates forward, and thus the overdrive stage is established.
The gear ratio in this case is 1 / (1 + ρ2), which is a value smaller than “1”.

<< Reverse >> First clutch means C1 and second clutch means C2 and second clutch means
The brake means B2 is engaged. That is, while the carrier 9 in the first planetary gear mechanism 1 and the carrier 10 in the second planetary gear mechanism are connected, the input is made to the ring gear 5 and the carrier 9 in the first planetary gear mechanism 1. In this case, the first planetary gear mechanism 1 rotates as a whole as in the case of the above-described third forward speed, so that the first planetary gear mechanism 1 rotates with respect to the second planetary gear mechanism 2. Although only the force is transmitted, in the second planetary gear mechanism 2, since the input is from the sun gear 4 with the carrier 10 fixed, the ring gear 6 is decelerated and rotated in the reverse direction. The rotation of 13 is a reverse rotation with deceleration with respect to the input shaft 11, and a reverse stage. The gear ratio in this case is −1 / ρ2.

In addition, the clutch means in the present invention is, as described comprehensively in the above-described embodiment, in short, it only needs to be able to connect necessary members to each other and release the connection. Therefore, a multi-plate clutch, a one-way clutch, or a configuration using both of them can be employed. Further, in terms of function, the input member and the many members may be individually connected and the connection may be released. The clutch means may be a single product having a function of simultaneously engaging and disengaging two or three other members of the input member, or a plurality of products having independent functions. You may. Also, in the present invention, the brake means is only required to be able to selectively fix each of the above-mentioned members, so that a one-way clutch disposed between a multi-disc brake, a band brake or a transmission case, or a combination of these one-way clutches Can be adopted.

Further, in the above embodiment, the speed ratio of the second speed is set to “1.60”.
The speed ratio of the third speed is configured to be "1.00". However, in the present invention, a speed ratio having an intermediate value between these speed ratios can be obtained. is there.

That is, the first and third clutches C1, C3 and the second brake B2 are engaged. In this case, the first planetary gear mechanism 1
In this case, the input is from the ring gear 5 with the carrier 9 fixed, so that the sun gear 3 rotates in the reverse direction at an increased speed.
In the planetary gear mechanism 2, the input is from the sun gear 4 in a state where the carrier 10 is fixed, so that the ring gear 6 is reduced in speed with respect to the sun gear 4 and rotates in the reverse direction. As a result, the deceleration positive rotation operation is performed as a whole, and the gear ratio is ρ1 / ρ2 (= 1.40).

Further, the first and third clutches C1, C3 and the first brake B1 are engaged. In this case, in the first planetary gear mechanism 1, the input is from the ring gear 5 in a state where the sun gear 3 is fixed, so that the carrier 9 rotates forward in the reduced speed, and in the second planetary gear mechanism 2, the sun gear 4 is fixed. Input from the carrier 10, the ring gear 6
And the motor rotates forward. As a result, the deceleration positive rotation operation is performed as a whole, and the speed ratio is 1 + ρ1 / 1 + ρ2 (= 1.12).

Effect of the Invention As described above, the transmission according to the present invention is a Simpson compound planetary gear mechanism mainly including two sets of single pinion type planetary gear mechanisms, and the carrier and the second planetary gear mechanism in the first planetary gear mechanism. Since the clutch means for selectively connecting the carrier and the ring gear in the first embodiment is provided and the input is selectively applied to the ring gear and the carrier of the first planetary gear mechanism, two sets of required planetary gear mechanisms are required. Is simple, and at least four forward speeds and one reverse speed, which are suitable for practical use including an overdrive speed, can be set. In addition, since no input is made to any of the sun gears, the input torque depends on the strength of the sun gear. However, it is possible to eliminate disadvantages such as being not restricted and reducing durability of the sun gear. Further, in the present invention, the carrier of the second planetary gear mechanism may be an input member that receives a rotational force from the input shaft and may be a fixed member. 1 Since the planetary gear mechanism is connected to the carrier and fixed as necessary,
It is easy to handle the connecting member for transmitting torque,
As a result, manufacture and assembly can be facilitated.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one embodiment of the present invention in principle. 1 ... first planetary gear mechanism, 2 ... second planetary gear mechanism, 3,
4 Sun gear, 5, 6 Ring gear, 9, 10 Carrier, 11 Input shaft, 13 Output shaft, C1, C2, C3, C4 Clutch means, B1, B2 Brake means .

Claims (1)

(57) [Claims] 1. Two sets of single pinion type planets having a sun gear, a ring gear concentrically disposed with respect to the sun gear, and a planet pinion disposed between the sun gear and the ring gear and meshing with the sun gear and the ring gear. The gear mechanism is coaxially arranged, and the sun gear of the first planetary gear mechanism and the sun gear of the second planetary gear mechanism are connected and integrated with each other, and the first
A clutch means for selectively connecting the carrier of the planetary gear mechanism to the carrier or ring gear of the second planetary gear mechanism or disengaging the connection is provided. The input shaft is selected between the ring gear and the carrier in the first planetary gear mechanism. And a clutch means for selectively preventing the rotation of each sun gear and the rotation of the carrier in the second planetary gear mechanism. A gear transmission for an automatic transmission, wherein an output shaft is connected to a ring gear.