JP2586018B2 - Continuously variable transmission - Google Patents

Description

The present invention relates to a continuously variable transmission that can be widely used in various industrial fields such as industrial machines and vehicles.

2. Description of the Related Art As a continuously variable transmission using a fluid pump / motor, a so-called fluid pressure transmission (HST) is known. However, although this is excellent in continuously variable transmission, its efficiency is not always good and the speed range is not satisfactory. Therefore, the HST and the differential gear mechanism are used in combination, and the transmission of power is shared between the HST and the differential gear mechanism, thereby exhibiting both the continuously variable transmission characteristics of the HST and the high efficiency of the gear transmission. Continuously variable transmission (HM
T) are being developed {references, hydraulic engineering (Tomoo Ishihara, Asakura Publishing), theory and practice of piston pump motors (Sadao Ishihara Corona)}. That is, the continuously variable transmission has first, second, and third input / output terminals, and a low-speed mechanical transmission that passes between the first input / output terminal and the second input / output terminal. And a differential mechanism forming a high-speed mechanical transmission system passing between the first input / output terminal and the third input / output terminal, and one differential input / output terminal of the differential mechanism. A fluid for connecting an input / output shaft of a fluid pump / motor and connecting the input / output shaft of the other fluid pump / motor to the third input / output end to form a variable speed fluid transmission system by both the pump / motor. A transmission mechanism, a low-speed side clutch for bringing a transmission end of the low-speed side mechanical transmission system into and away from a common rotating element provided on an input side or an output side, and a transmission end of the high-speed side mechanical transmission system. A high-speed side clutch that comes into contact with and separates from the common rotating element, and By switching the manner, and is configured so as to select one of the low-speed mode or the high speed mode. Conventionally, a dry or wet multi-plate clutch has been used as the clutch.

[Problems to be Solved by the Invention] However, a multi-plate clutch tends to be bulky with many parts. Therefore, when such a clutch is incorporated in the mode switching portion, it is difficult to reduce the size and weight of the entire device. Also, this kind of clutch is
Since the power transmission state is smoothly switched by utilizing the slip between the clutch plates having a large area, energy loss at the time of switching is large. In addition, in such a case, since the clutch plate is easily worn, there is a problem that maintenance is troublesome.

In order to cope with such inconvenience, it is conceivable to use a mode switching portion that can obtain a simple and reliable transmission state, such as a dog clutch, etc. It is necessary to switch quickly at the moment when the rotation speed of the transmission end of each mechanical transmission system and the rotation speed of the common rotary element exactly match. For this reason, there is a problem that a very accurate rotational speed detector and an actuator that operates reliably and quickly based on the detection result of the rotational speed detector are required.

An object of the present invention is to solve all of the above problems.

[Means for Solving the Problems] The present invention employs the following configuration in order to achieve such an object.

That is, the continuously variable transmission according to the present invention has the first, second, and third input / output terminals, and has a low-speed side that passes between the first input / output terminal and the second input / output terminal. A differential mechanism forming a mechanical transmission system and a high-speed mechanical transmission system passing between the first input / output terminal and the third input / output terminal; and a second input / output terminal of the differential mechanism To the input / output shaft of one of the fluid pumps / motors, and to the third input / output end, to the input / output shafts of the other fluid pump / motor.
A fluid transmission mechanism that forms a variable-speed hydraulic transmission system by a motor; and a low-speed side synchromesh type that moves and separates the transmission end of the low-speed side mechanical transmission system to or from a common rotary element provided on the input or output side. It is characterized by comprising a power intermittent mechanism and a high-speed synchromesh power intermittent mechanism for bringing the transmission end of the high-speed mechanical transmission system into and out of contact with the common rotating element.

As the synchromesh type power interrupting mechanism, for example, an inertia lock type or a constant load type used in a vehicle transmission can be applied.

[Operation] With such a configuration, in the low-speed mode, the transmission end of the mechanical transmission system on the low-speed side that passes between the first input / output end and the second input / output end of the differential mechanism. Is connected to a common rotating element provided on the output side or the input side via a low-speed side synchromesh type power interrupting mechanism, and a part of the input power is directly output through the low-speed side mechanical transmission system. . Further, the remaining power is guided to the output side through a fluid transmission system formed by the fluid transmission mechanism. In this case,
One fluid pump / motor functions as a motor, and the other fluid pump / motor performs a function as a pump.

In the high-speed mode, the transmission end of the mechanical transmission system on the high-speed side that passes between the first input / output end and the third input / output end of the differential mechanism has the synchromesh type power interrupting mechanism on the high-speed side. A part of the input power is directly output through the high-speed side mechanical transmission system. Further, the remaining power is guided to the output side through a hydraulic power transmission system formed by a fluid power transmission mechanism. In this case, the functions of the fluid pumps / motors as pumps and motors are replaced with those described above.

The switching from the low speed mode to the high speed mode is performed as follows. That is, in a state where only the low-speed side synchromesh type power interrupting mechanism is connected, the rotation speed of the transmission end of the high-speed side mechanical transmission system approaches the rotation speed of the transmission end of the low-speed side mechanical power transmission system. At this time, an operation to connect to the high-speed side synchromesh type power interrupting mechanism is added. Then, when the rotational speeds of the two transmission ends become equal, the high-speed side synchromesh type power interrupting mechanism is automatically connected, and the transmission end of the high-speed side mechanical power transmission system is connected to the common rotary element. Is done. Thereafter, by switching the low-speed side synchromesh type power interrupting mechanism to the non-connection state, the high-speed mode is established. When switching from the high-speed mode to the low-speed mode, the reverse operation may be performed.

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

As shown schematically in FIG. 1, the continuously variable transmission according to the present invention has first, second, and third input / output terminals 1, 2, and 3, and the first input / output terminal 1, Mechanical transmission system a passing between the first input / output terminal 1 and the third input / output terminal 3 and a low-speed mechanical transmission system a passing between the first input / output terminal 1 and the third input / output terminal 3. A differential mechanism 4 forming a system b, and an input / output shaft 7a of one of the fluid pump / motors 7 is connected to the second input / output end 2 of the differential mechanism 4 via gears 5 and 6, and 3
The input / output end of the other fluid pump / motor 8
8a is connected via gears 9 and 11, and a fluid transmission mechanism 12 which forms fluid transmission systems A and B of variable speed by both pumps / motors 7 and 8; and a transmission of the mechanical transmission system a on the low speed side. A low-speed side synchromesh type power interrupting mechanism 14 for moving the end to and away from the center boss 13 serving as a common rotating element, and a high-speed side synchronizing mechanism for moving the transmission end of the high-speed side mechanical transmission system b to and away from the center boss 13. And a mesh-type power intermittent mechanism 15. Then, the center boss 13 is moved to the gear 16 and
It is connected to an output shaft 18 via 17.

The differential mechanism 4 is of a planetary gear type in which a sun gear 22 is provided inside a plurality of planetary gears 21 provided at equal intervals in the circumferential direction, and a ring gear 23 is meshed with the outside. The center of a retainer 24 that supports each planetary gear 21 is the first input / output end 1, and the input / output end 1 is provided with an input shaft 25 connected to the power source 19. The tip of the support shaft 22a of the sun gear 22 is the second input / output end 2, and the gear 5 is fixed to the input / output end 2. Further, the boss portion of the ring gear 23
The tip of 23a is the third input / output end 3, and the gear 9 is provided at the input / output end 3. Thus, the mechanical transmission system a on the low speed side includes the planetary gear 21 and the sun gear 2.
2, a gear 5, a gear 6, a gear 28 and a gear 29, and a boss 29a of the last gear 29 plays a role as a transmission end of the mechanical transmission system a. On the other hand, the mechanical transmission system b on the high-speed side is composed of the planetary gear 21 and the ring gear 23, and the boss 23a of the ring gear 23 serves as a transmission end of the mechanical transmission system b. I have.

The fluid transmission mechanism 12 is configured by connecting a variable displacement fluid pump / motor 7 and a variable displacement fluid pump / motor 8 in series via a hydraulic circuit 31 similar to a normal HST. Yes, the input / output shaft 7a of the fluid pump / motor 7
Is connected to the support shaft 22a of the sun gear 22 via gears 6 and 5, and the input / output shaft 8a of the fluid pump / motor 8 is connected to the ring gear 23 via gears 11 and 9. Reference numeral 32 denotes a boost pump connected to the hydraulic circuit 31. Further, the low-speed side synchromesh type power interrupting mechanism 14 is of a so-called inertia lock type, and has one end of the center boss 13 and a boss portion 29 of a gear 29 forming a transmission end of the low-speed side mechanical transmission system a. Between
A dog gear 41 and a synchronizer ring 42 are provided. The dog gear 41 is fixed to the boss portion 29a of the gear 29, and a pointed end 41b is provided on the outer periphery thereof with the center boss 1a.
It has teeth 41a oriented in three directions. On the outer periphery of the boss portion of the dog gear 41, a cone clutch surface 41c having a gradually decreasing diameter toward the center boss 13 is formed, and the synchronizer ring 42 is slidably fitted to the cone clutch surface 41c. . The synchronizer ring 42 has teeth 42a on its outer periphery with a pointed end 42b facing the center boss 13, and concave portions 42c are formed at a plurality of positions on the end face. On the other hand, on the outer periphery of the center boss 13, the teeth 41a of the dog clutch 41 and the teeth 42a of the synchronizer ring 42
A spline 43 having the same effective diameter and pitch is formed, and a spline 45 engraved on the inner periphery of the sleeve 44 is slidably engaged with the spline 43 in the axial direction. A cutout groove 46 is formed in a portion of the center boss 13 corresponding to the recessed portion 42c, and the cutout groove 46 is opened at an end face thereof.
Are engaged with each other. The synchronizer key
The width dimension of 47 is set to a value substantially equal to the circumferential opening width dimension of the notch groove 46. Therefore, these synchronizer keys 47 are slidable only in the axial direction and the radial direction of the center boss 13. Each synchronizer key 47 is urged outward by a spring 48,
The tip is inserted into the recess 42c of the synchronizer ring 42. A convex portion 47a is provided on the outer surface of each synchronizer key 47, and the convex portion 47a is elastically engaged with a shallow concave portion 45a provided on the inner periphery of the spline 45 of the sleeve 44. An annular groove 44 is provided on the outer periphery of the sleeve 44.
a is formed, and a shifter 49 driven in the axial direction by hydraulic pressure or the like is engaged with the annular groove 44a.

The operation of the synchromesh type power interrupting mechanism 14 will be described as follows. In the release position shown in FIGS. 2 and 3, the recess of the spline 45 provided in the sleeve 44 is provided.
The projection 45a of the synchronizer key 47 is engaged with the projection 45a, and the tip of the synchronizer key 47 is loosely fitted in the recess 42c of the synchronizer ring 42. From this state, when the shifter 49 is urged rightward in the drawing to move the sleeve 44 in the direction of the synchronizer ring 42, first, the tip of the synchronizer key 47 is moved to the concave portion 42 of the synchronizer ring 42.
The synchronizer ring 42 is pressed against the cone clutch surface 41c of the dog gear 41 (see FIG. 4). As a result, the synchronizer ring 42 tries to follow the dog gear 41 by friction. When the sleeve 44 is further moved rightward in the figure from this state, the convex portion 47a of the synchronizer key 42 comes off from the concave portion 45a provided on the inner periphery of the sleeve 44, and the synchronizer key 4
7 is pressed inward by the inner circumference of the sleeve 44. Therefore, the synchronizer key 47 is pressed against the cone clutch surface 41c of the dog gear 41 with a stronger force, and a strong relative frictional force acts between the synchronizer ring 42 and the dog gear 41. Therefore, the synchronizer ring 42 is urged to a position where the synchronizer ring 42 is most deviated relative to the center boss 13, that is, a position where the inner side surface of the concave portion 42c contacts the side surface of the synchronizer key 47 (see FIG. 5). . In this position, the slope forming the point 45b of the spline 45 of the sleeve 44 and the slope forming the point 42b of the tooth 42 of the synchronizer ring 42 abut against each other, and the sleeve 44 is moved further rightward in the drawing. To prevent it from moving forward. In this state, the dog gear
When the relative rotational speed difference between 41 and the center boss 13 decreases, the frictional force acting on the synchronizer ring 42 from the cone clutch surface 41c of the dog gear 41 decreases. Therefore, at the stage where the rotation of the dog gear 41 and the center boss 13 is substantially synchronized and the frictional force is substantially eliminated, the sleeve 44 guides the synchronizer ring 42 by the frictional force due to the guiding action of the slopes of the sharp ends 42b and 45b. It is possible to push back in the direction opposite to the direction in which the gear is shifted, and the sleeve 44 advances, and the spline 45 meshes with the teeth 41a of the dog gear 41 (see FIG. 6).

On the other hand, the high-speed synchromesh type power interrupting mechanism 15
Is provided with a dog gear 51 and a synchronizer ring 52 between the other end of the center boss 13 and the boss 23a of the ring gear 23 forming the transmission end of the mechanical transmission system b on the high-speed side. . The dog gear 51 is fixed to the boss 23a of the ring gear 23, and has teeth 51a on its outer periphery with a pointed end 51b directed toward the center boss 13. On the outer periphery of the boss portion of the dog gear 51, a cone clutch surface 51c having a gradually decreasing diameter toward the center boss 13 is formed, and the synchronizer ring 52 is slidably fitted to the cone clutch surface 51c. . The synchronizer ring 52 has teeth 52a on its outer periphery with a pointed end 52b facing the center boss 13.
Are formed. On the other hand, on the outer periphery of the center boss 13,
A spline 53 having the same effective diameter and pitch as the teeth 51a of the dock clutch 51 and the teeth 52a of the synchronizer ring 52 is formed, and a spline 55 engraved on the inner periphery of a sleeve 54 is formed on the spline 53. Are slidably engaged in the same direction. A cutout groove 56 is formed in a portion of the center boss 13 corresponding to the concave portion 52c. The cutout groove 56 is opened at an end face thereof, and a synchronizer key 57 is engaged with each of the cutout grooves 56. Note that the width of the synchronizer key 57 is set to a value substantially equal to the circumferential opening width of the notch groove 56. Therefore, each of these synchronizer keys 57 is
Can be slid only in the axial direction and the radial direction.
Each synchronizer key 57 is urged outward by a spring 58, and its tip is the synchronizer ring.
52 is inserted into the recess 52c. A convex portion 57a is provided on the outer surface of each synchronizer key 57, and the convex portion 57a is a shallow concave portion 55 provided on the inner periphery of the spline 55 of the sleeve 54.
It is elastically engaged with a. An annular groove 54a is formed on the outer periphery of the sleeve 54, and a shift 59 driven in the axial direction by hydraulic pressure or the like is engaged with the annular groove 54a.

The high-speed synchromesh type power interrupting mechanism 15 also operates and interrupts the power by performing the same operation as the low-speed power interrupting mechanism.

In the drawing, reference numeral 61 denotes a rotation speed detector for detecting the rotation speed of the transmission end of the low-speed mechanical transmission system a, and 62 detects the rotation speed of the transmission end of the high-speed mechanical transmission system b. Rotation speed detector.

 Next, the operation of the entire continuously variable transmission will be described.

In a low-speed mode in which the low-speed synchromesh type power interrupting mechanism 14 is connected and the high-speed synchromesh type power interrupting mechanism 15 is released, the first
The input side and the output side are directly connected via a low-speed mechanical transmission system a passing between the input / output end 1 and the second input / output end 2 of the motor, and part of the input power is It is transmitted directly to the output shaft through the transmission system a. At this time, as shown in FIG. 7, the one fluid pump / motor 7 functions as a motor, and the other fluid pump / motor functions as a pump. That is, the third input / output end 3 of the differential mechanism 4
Is transmitted to the output shaft 18 through a hydraulic power transmission system A formed between the pumps / motors 7 and 8. In the low-speed mode, the pump capacity of the other fluid pump / motor 8 is increased, and after the capacity is maximized, the one fluid pump / motor 7 is increased.
By gradually reducing the motor capacity of the output shaft 18, the rotation speed of the output shaft 18 with respect to the rotation of the input shaft 25 increases. In other words, if the capacity of the other fluid pump / motor 8 is zero, the third mechanism 4
Since the input / output end 3 of the differential mechanism 4 is in a substantially idling state, the output shaft 18 connected to the second input / output end 2 of the differential mechanism 4 is substantially stopped. Then, as the capacity of the fluid pump / motor 8 is increased, the rotation speed of the third input / output terminal 3 is relatively reduced, and the rotation speed of the second input / output terminal 2 is relatively reduced. Will gradually increase.

When the speed of the dog gear 41 connected to the transmission end of the low-speed mechanical transmission system a and the speed of the dog gear 51 connected to the transmission end of the high-speed mechanical transmission system b become equal, Is performed, and the mode is switched to the high-speed mode.

In this high-speed mode, a mechanical transmission system b that passes between the first input / output terminal 1 and the third input / output terminal 3 of the differential mechanism 4 is formed, and a part of the input power is It is transmitted directly to the output shaft 18 through the mechanical transmission system b. At this time, as shown in FIG. 7, the one fluid pump / motor 7 functions as a pump and the other fluid pump / motor 8
Works as a motor. That is, the second mechanism of the differential mechanism 4
Is transmitted to the output end 18 through a fluid transmission system B formed between the one fluid pump / motor 7 and the other fluid pump / motor 8. In this high-speed mode, the pump capacity of the one fluid pump / motor 7 is gradually increased, and after the capacity is maximized, the motor capacity of the other fluid pump / motor 8 is gradually reduced. The rotation speed of the output shaft 18 with respect to the rotation speed of the input shaft 25 will increase.

Here, the operation when switching from the low speed mode to the high speed mode will be described. There synchromesh type power interrupting mechanism 14 of the low speed side in the connected state, in the low speed mode synchromesh-type power interrupting mechanism 15 of the high-speed side is in the released state, the rotation speed R ₁ of Doggugya 41 of the low speed side is high side Doggugya
51 is closer to the rotation speed R ₂ of the case where the difference is smaller than the set value R _0, activates the high-speed side of the shifter 59 moves the sleeve 54 to the left in FIG. As a result, the synchronizing operation described above is performed, and when the high-speed dog gear 51 is synchronized with the center boss 13 that rotates integrally with the low-speed dog gear 41, the spline 55 of the high-speed sleeve 54 is shifted to the high-speed dog gear. The dog gear 51 meshes with the teeth 51a. That is,
The high-speed side synchromesh type power interrupting mechanism 15 is connected. This state is confirmed by detecting the position of the shifter 59 or the like, and thereafter, the low-speed side shifter 49 is operated to operate the sleeve 44 to the left in the drawing, and the spline 45 of the sleeve 44 and the low-speed side The state of engagement with the dog gear 41 is released. Note that this low-speed side sleeve 44 is
When the motor is removed from the motor, the capacity of the fluid pump / motor 7 is slightly increased to make the torque transmitted from the dog gear 41 on the low speed side to the center boss 13 substantially zero. As a result, as shown in FIG. 3, only the high-speed side synchromesh type power interrupting mechanism 15 is connected, and the high-speed mode is set. When shifting from the high-speed mode to the low-speed mode, the above process may be reversed.

In this way, switching between the high-speed mode and the high-speed mode can be performed. However, this device has a synchromesh type having a much smaller number of parts and a simple structure than the multiple disc clutch at the switching portion. Power intermittent mechanisms 14 and 15 are used. Therefore, the size and weight of the entire device can be reduced. In addition, the synchromesh type power interrupting mechanism 1
Parts 4 and 15 have less wear of parts than multi-plate clutches and are easier to maintain. Further, it is not necessary to perform a delicate operation such as connecting a large number of clutch plates while sliding them as in the case of a multi-plate clutch. Therefore, switching can be reliably performed by a simple actuator, and energy loss at the time of switching can be effectively suppressed.

In addition, the synchromesh type power interrupting mechanism can reliably switch the mode only by detecting that the rotation speeds of the center boss and the transmission end of each transmission system substantially match, and executing the shift operation. Therefore, as in the case where a simple dog clutch is used, the capacity of the fluid pump / motor is controlled with high precision, and the switching operation is performed at the moment when the rotation speeds of the center boss and the transmission end of each transmission system are exactly the same. There is no restriction that it must be. Therefore, a desired switching control can be performed without any trouble using an inexpensive rotational speed detector having relatively low accuracy.

The configuration of the synchromesh type power interrupting mechanism is not limited to the above-described one, and various modifications can be made without departing from the spirit of the present invention, such as using a constant load type.

Further, the differential mechanism is not limited to the planetary gear type as described above.

Further, the configuration of the fluid transmission mechanism is not limited to that of the above-described embodiment. For example, one fluid pump /
Various modifications are possible, such as using a fixed displacement motor.

In the above-described embodiment, the input distribution type in which the differential mechanism is disposed on the input side has been described. However, the present invention can be similarly applied to the output distribution type.

[Effects of the Invention] Since the present invention has the above-described configuration, it can be reduced in size and weight, and is easy to maintain.
It is an object of the present invention to provide an excellent continuously variable transmission capable of performing mode switching smoothly and reliably without using a highly accurate rotation speed detector or control device.

[Brief description of the drawings]

1 shows an embodiment of the present invention, FIG.
FIG. 2 is a sectional view showing a synchromesh type power interrupting mechanism, FIG. 3 is an enlarged partial sectional view showing a synchronizer key portion of the synchromesh type power interrupting mechanism, and FIGS. FIG. 7 is an explanatory diagram showing a control pattern. DESCRIPTION OF SYMBOLS 1 ... 1st input / output terminal 2 ... 2nd input / output terminal 3 ... 3rd input / output terminal 4 ... Differential mechanism 7 ... One fluid pump / motor 8 ... The other fluid Pump / Motor 12 Fluid transmission mechanism 13 Common rotary element (center boss) 14 Synchromesh type power intermittent mechanism 15 Synchromesh type power intermittent mechanism 41 Transmission end (dog gear) 51 Transmission end (Dog gear)

Claims (1)

(57) [Claims] 1. A low-speed mechanical transmission system having first, second, and third input / output terminals and passing between the first input / output terminal and the second input / output terminal. Mechanism that forms a high-speed mechanical transmission system that passes between the input / output end of the differential mechanism and the third input / output end, and one fluid pump / motor is provided at the second input / output end of the differential mechanism. And the third input / output shaft
A fluid transmission mechanism that connects the input / output shaft of the other fluid pump / motor to the input / output end of the other and forms a variable speed hydraulic transmission system with both pumps / motors; and a transmission end of the mechanical transmission system on the low speed side. A low-speed side synchromesh type power interrupting mechanism that makes and breaks a common rotating element provided on the input side or the output side, and a high-speed side that makes the transmission end of the high-speed mechanical transmission system approach and separates from the common rotating element. A continuously variable transmission, comprising: a synchromesh type power interrupting mechanism.