JPS6388328A - Torque transmitter - Google Patents

Abstract

PURPOSE:To improve durability and reliability by inserting into the 1st rotation member the 2nd rotation member which forms a mechanism which connects fluid chambers of a coordinate phase changing their volumes with cam-bodies reciprocating in a diametric direction. CONSTITUTION:A rotor 40 provided with cylindrical holes 42 in confrontation with a cam surface 31 is inserted into a drive-housing 30 fixed to an input shaft and forming the cam surface 31 on its inner perimeter. Oil chambers 60 are formed by inserting in an oil-tight condition into these cylindrical holes 42 driving pistons 50 which have spherical surfaces 50a slide-contacting with the cam surface 31 and reciprocate at a time of the relative rotation of the input and output shafts. Also, oil chambers 60 of a coordinate phase are connected with oil passages 61a, 2 provided with an orifice 62 and a check valve 64. Accordingly, a torque transmission characteristic which is added with a transmission torque element generated by a centrifugal force element is obtained, so a transmitter is compact and restrains the lowering of transmission torque and prevents the occurrence of a collision sound and is inexpensive and can improve reliability.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a drive force distribution device for a multi-wheel drive vehicle such as a four-wheel drive vehicle, a differential device for left and right wheels, and a limiter for differential differential between left and right wheels. The present invention relates to a torque transmission device used as a differential limiting device, etc.

(Prior Art) As a conventional torque transmission device, for example,
A device as described in Japanese Patent No. 116529 is known.

This conventional device includes a first rotating shaft that transmits driving force to the front wheels, a second rotating shaft that transmits driving force to the rear wheels, and a second rotating shaft that transmits driving force to the front wheels.
and a hydraulic pump that is used as a connecting means for the second rotating shaft, is driven by the difference in rotational speed between the first and second rotating shafts, and discharges an amount of oil according to the difference in rotational speed. The conventional torque transmission device is characterized in that an auxiliary oil passage having an oil flow control means is provided in the discharge passage and the suction oil extraction passage of the hydraulic pump. A device as described in Japanese Patent Publication No. 54-4134 is also known.

This prior art device includes a first rotary member journaled within a static housing, an input rotary member extending within the housing and rotatably coupled to the first rotary member, and an input rotary member adjacent and coaxial with the first rotary member. a second rotating member disposed in the housing, a first output rotating member extending within the housing and rotatably coupled to the second rotating member, a second output rotating member rotatably coupled to the input member; The members are connected, and under predetermined fluid pressure conditions, the input torque from the input member is transmitted to the first output rotating member at a selected rate, and the remaining 14 of the torque transmitted from the input member is transferred to the second output rotating member. It comprises a fluid means for transmitting to the member and a selection means for adjusting a predetermined fluid pressure condition for operating to adjust the proportion of torque that the fluid means transmits to the output member.

(Problem to be solved by the invention) However, the former conventional device
29! ;) had the following problems.

(V) Since the hydraulic control circuit 21 is formed in the rotating housing on the cam ring 20b side, which is located far away from the rotational center axis in the radial direction, when the rotating housing rotates at high speeds such as at high vehicle speeds, the oil passage Centrifugal force acts on the hydraulic fluid flowing through the pump and the relief valve, and this centrifugal force can cause the oil pressure level generated by the hydraulic pump to not reach the desired oil pressure level, or conversely cause the oil pressure level to become too high. Therefore, a stable torque transmission effect cannot be expected.

(2) Since the hydraulic control circuit 21 is formed in the rotary housing, this hydraulic control circuit 21 causes the mass imbalance of the rotary housing. Whirling vibration occurs.

(3) Also, as shown in the drawings in the publication, since a vane pump is used as a hydraulic pump that discharges oil according to the difference in rotational speed, oil leaks in areas where the difference in rotational speed is small (vane pumps generally (difficult to ensure sealing), sufficient hydraulic pressure is not generated, and therefore, when this conventional device is used in a four-wheel drive vehicle, the torque transmission effect is required to prevent extremely large wheel slip. I can't hope for it.

Also, the latter's conventional outfit? i (Special Publication No. 54-4134)
There are problems as described below.

■ Since the cam surface 114 of the fluid means is formed on the outer circumferential surface of the inner rotating member, the diameter of the entire cam surface is smaller than when the cam surface is formed on the inner circumferential surface of the outer rotating member.
It is difficult to increase the machining accuracy of the cam surface, and in order to generate a flow rate of 1 minute, the unevenness of the cam surface must be increased, but since the overall diameter of the cam surface is small, the unevenness The difference in level is not smooth, and a collision hill with the piston head occurs during rotation.

Since the flow resistance is determined by the check valve regardless of the rotational speed difference, even when turning on a high friction coefficient road where there is a slight difference in rotational speed, the 4-wheel drive condition yπ; (6-wheel drive condition ym) This results in a tight corner braking phenomenon.

・6. ) Furthermore, since the piston 124 is arranged so as to contact the cam surface 114 from the outside in the radial direction, when the first rotating member 90 in which the piston 124 is skewed at high speeds rotates at a high speed, The centrifugal force acting on the piston 124 acts in the direction of reducing the contact force with the cam surface 114, and although generally speaking, the higher the vehicle speed, the better the driving force distribution to the four-wheel drive side. As for the transmission characteristics, the higher the vehicle speed is, the smaller the transmission torque becomes, and exhibits +F characteristics.

In response to such prior art, V. Motoyama filed Japanese Patent Application No. 129424/1983 as a prior application to solve the above-mentioned problems.

However, in this prior art, since only one orifice was provided for fluid drainage formed by two cam bodies, the following problems remained.

■ Due to variations in orifice diameter, the pressure in fluid chambers of the same phase tends to become unbalanced, impairing the durability of the cam body.

Since the flow rate per orifice is small, the orifice diameter must be reduced in order to secure the torque capacity, and when converted to the same torque capacity, the orifice diameter becomes smaller, resulting in contamination (internal dust). ).

(9) The number of parts such as orifices is large, the cost is high, and the reliability is low.

(Means for Solving the Problems) The present invention aims to solve the above-mentioned problems, and in order to achieve the above-mentioned problems, the present invention provides an input/output system that is non-rotatable and has fast input/output. A torque generating means is provided between the shafts for causing a fluid to flow according to a rotational speed difference between the two shafts, and the transmission torque between the input and output shafts is controlled by the flow resistance of the fluid. In the transmission device, the flow rate generating means includes a first rotating member that is formed integrally with one of the input/output shafts and has a cam surface on the inner peripheral portion, and a first rotating member that is formed integrally with the other input/output shaft and generates the force L. a second rotating member inserted into the plane; a cam body supported by the second rotating member and in circumferential contact with the cam surface and reciprocating in the radial direction when the two rotating members rotate relative to each other; a plurality of fluid chambers whose volume changes with reciprocating motion; a fluid path formed in the second rotating member and connecting each fluid chamber via an orifice; and a plurality of fluids that are in the same phase during the reciprocating stroke of the cam body. a communication path that communicates the chambers with each other;
It is characterized by being a means equipped with the following.

(Function) Therefore, in the torque transmission device of the present invention, since the means as described in J-2 is used, the fl.
When relative rotation occurs, the cam body surrounding the cam surface reciprocates in the radial direction according to the shape of the cam surface, and in the fluid chamber whose volume changes due to the reciprocating movement of the cam body, due to flow resistance due to the orifice. Fluid pressure is generated and the cam body is pushed against the cam surface by this fluid pressure, thereby transmitting torque corresponding to the relative rotational speed difference between the two rotating members.

When the absolute rotational speed of the second rotating member on which the cam body is provided is high, that is, at high vehicle speeds, the centrifugal force acting on the cam body acts to increase the pressing force against the cam surface, so the torque transmission characteristics , the transmission torque increases according to the relative rotational speed difference, and the higher the vehicle speed, the more the transmission torque generated by centrifugal force is added.

In addition, since the cam body is provided with a communication path that communicates a plurality of fluid chambers in the same phase with each other during the reciprocating stroke, the pressure balance between the same phases can be maintained, and the fluid with a volume of at least two fluid chambers can be maintained. Since the amount is reduced by one orifice,
The orifice area can be set to more than double while maintaining the same throttling effect, and the effects of contamination can also be prevented.

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a torque transmission device provided in an engine drive power transmission system of a four-wheel drive vehicle will be taken as an example.

First, a torque transmission device A according to an embodiment will be described based on the drawings shown in FIGS. 1 to 4.

The torque transmission device A of the embodiment, as shown in No. 41J,
It is installed in the middle of the rear wheel drive system of a four-wheel drive vehicle based on front wheel drive as a device that serves as both a center differential and a device for controlling drive force distribution to the rear wheels.

The drive system of a four-wheel drive vehicle to which the embodiment device A is applied includes, as a front wheel drive system, an engine 1, a transmission (including a clutch) 2. It is equipped with a front differential 3, a front dry shaft 4.5, a front drive shaft joint 6..., front wheels 7, 8, and as a rear wheel drive system, a transfer gear train 9, a front propeller shaft 10, a center propeller shaft ( input shaft) 11, torque transmission device A1, rear propeller shaft (output shaft) 12, propeller shaft joint 13...
, a center bearing 14, a rear differential 15, a rear drive shaft 16, 17, a rear drive shaft joint 18, and a rear wheel 19, 20.

The front differential 3 is a differential device for the front wheels 7.8 that is interposed between the final gear 21 of the transmission 2 and the front drive shafts 4, 5.

The transfer gear train 9 is a driving force splitting device that extracts engine driving force from the differential case 22 of the front differential 3 to the rear wheels 19, 20 side, and is housed in a transaxle case 23 together with the transfer gear train 9 and the front differential 3. It is being

The rear differential 15 is a differential device for the rear wheels 19.20 that is interposed between the rear propeller shaft 12 and the rear drive shaft 16.17.

The configuration of the torque transmission device A of the embodiment will be explained.

As shown in FIGS. 1 and 2, the embodiment device A includes a drive housing (first rotating member) 30, a cam surface 31, a rotor (second rotating member) 40, a driving piston (
cam body) 50, oil chamber (fluid chamber) 60, oil passage (fluid passage) 6
1. The main components are an orifice 62 and a communication path 63.

The drive housing 30 is a member that is provided integrally with the center propeller shaft 11, which is an input shaft, by means of a port IL, etc., and has a substantially square cam surface 31 formed on its inner circumference.

The rotor 40 is inserted into the cam 31 of the drive housing 30, and the rear propeller shaft 12, which is an output shaft, is integrally provided with bolts or the like, and is also screwed to the drive housing 30. The stopper plate 41 is provided in a fixed state in the axial direction while allowing relative rotation.

The rotor 40 has four cylinder holes 42 arranged at equal intervals in the radial direction at positions facing the cam surface 31.
... is formed.

The driving piston 50 is connected to the cylinder hole 42.
On the other hand, the cam member is provided in an oil-tight state by a seal ring 51, and the circumferential surface with the cam surface 31 is formed into a spherical surface 50a to ensure smooth contact movement, and the circumferential direction is 4.
It circumferentially contacts the cam surface 31 at a position offset by 5 degrees, and reciprocates when the drive housing 30 and rotor 40 rotate relative to each other.

The radius of curvature of the spherical surface 50a is smaller than that of the cam surface 31, but is set larger than that of the driving pole that matches the diameter of the cylinder hole 42, and the Hertzian contact stress is high.
It is designed to withstand high capacity (high torque).

The oil chamber 60 is a chamber formed between the cylinder hole 42 and the driving piston 50, and changes in volume as the driving piston 50 reciprocates.

The oil passage 61 is a passage formed in the rotor 40 so as to connect each oil chamber 60, and has an orifice 62 and a check valve 64 corresponding to a pair of opposing cylinder holes 42.
is provided.

The oil passage 61 is composed of a radial oil passage 61a formed at the bottom of each cylinder hole 42, and an axial oil passage 61b formed at the axis of the rotor 40, which face each other. Oil chamber 6
A set of orifices 6 are provided in each oil passage 61 connecting the 0.60
2 and a check valve 64 are provided. That is, two driving pistons 50 are provided with a set of orifices 62 and check valves 64.

Further, the opening end of the axial oil passage 61b is led to an accumulator chamber 74, and the steep driving piston 5
It is designed to absorb fluctuations in oil amount due to reciprocating motion of the engine. This is set so that the total volume remains almost constant at all relative rotation positions even if there is a change in volume in each oil chamber 60, but when there is a sudden relative rotation or a large relative rotation, the total volume is This is because significant volume fluctuations occur.

Incidentally, the accumulator chamber 74 shown in FIGS. 1 and 2 is
An accumulator piston 65 that is reciprocatably provided in an oil-tight state on the rotor 40, and a coil spring 6 that is interposed between the piston 65 and a spring retainer 66.
7, the accumulator piston 65 is provided with a seal plug 68 for air and oil removal in the center (on the central axis), and this seal plug 68 prevents rotational imbalance. At the same time, air and oil removal work can be done effectively in a short time.

Another example of the accumulator chamber 64 shown in FIG.
and a disc spring 71 interposed between the accumulator piston 69 and the accumulator piston 69, and the accumulator piston 69 has a seal plug 7 for air and oil drainage similar to the previous example in its center.
2 was established.

The communication passage 63 is an oil passage that communicates a plurality of oil chambers 60, 60 (in the embodiment, two opposing chambers) that are in the same phase during the reciprocating stroke of the driving piston 50, and has three communication passages. The passages 63.63.63 are formed so as not to interfere with each other.

Next, the operation of the embodiment will be explained.

(B) When no rotational speed difference ΔN occurs When driving in a straight line at low to medium speeds on a dry asphalt road, etc., when no rotational speed difference ΔN occurs between the front and rear wheels,
Since there is no relative rotation between the drive housing 30 and the rotor 40 and the driving piston 50 does not reciprocate in the radial direction, there is no transmission torque ΔT transmitted to the rear wheels 19, 20 by the torque transmission device A, and the engine driving force is front wheel 7,
It becomes a front wheel drive state where the transmission is transmitted only to 8.

However, even when the rotational speed difference ΔN does not occur between the front and rear wheels, when driving straight on a highway at high speed, the rotor 4 rotates at high speed as the rear wheels 19.20 rotate.
Centrifugal force Fc acts on the driving piston 50 provided at 0, and the driving piston 50 is pressed against the cam surface 31 by this centrifugal force Fc, as shown in FIG. , transmission torque ΔTco will be generated. In addition, the centrifugal force Fc is m'v2 Fc=- m; Mass (driving piston) r; Distance from the rotation center axis to the mass center of gravity V; Rotor rotation speed, and the rotation speed V, that is, the square of the vehicle speed ■ occurs in proportion to.

Therefore, when driving straight at high speed on a highway, etc., the rear wheel 19
．． The transmission torque ΔTco to the 20 side is generated, resulting in a four-wheel drive state, and high-speed straight running stability can be improved.

(b) When a rotational speed difference ΔN occurs When starting or accelerating by suddenly pressing the accelerator pedal, or when driving on a mountain road, snowy road, muddy ground, etc., the front wheels 7 and 8 are the driving wheels. slips, and there is a rotational speed difference Δ between the front and rear wheels.
When N occurs, relative rotation occurs between the drive housing 30 and the rotor 40, and due to this relative rotation, the driving piston 50 that contacts the cam surfaces 31 and 32 reciprocates in the radial direction. When trying to reduce the volume of the oil chamber 60 by moving toward the center of the rotation axis, the pressure inside the oil chamber 60 increases due to the flow resistance caused by the orifice 62, and this generated oil pressure is multiplied by the pressure receiving area of the piston 50. The hydraulic pressure becomes a force that presses the driving piston 50 against the cam surface 31, and this pressing is caused by the force that causes the rear wheel 19 to press against the cam surface 31.
．． 76 transmission torques to the 20 side are generated.

The torque ΔT transmitted to the rear wheels 19, 20 is expressed as a quadratic function, as shown by the solid line in FIG. The curve shows the transmission torque characteristics,
The higher the vehicle speed V is, the more transmission torque ΔTc due to centrifugal force is added.

Therefore, when the front wheels 7 and 8 slip, the front wheels 7 and 8 slip.
Automatically switches to front-wheel drive depending on the degree of slippage! Drive force distribution will be controlled from the 4-wheel drive state to the 4-wheel drive state, improving starting performance and acceleration performance, and improving drivability on mountain roads and snowy roads.
Also, it is possible to improve the ability to escape from muddy ground.

In addition, even when making a small turn at low speed, a slight rotational speed difference ΔN occurs between the front and rear wheels due to the difference in the turning trajectory between the front and rear wheels, but at this time, the torque ΔT transmitted to the rear wheel 19.20 side is small. Therefore, the rotational speed difference ΔN between the front and rear wheels is absorbed by the torque transmission device A (center differential function), and the tight corner braking phenomenon is prevented from occurring.

In addition, when turning at high speed, a large rotational speed difference ΔN occurs between the front and rear wheels, resulting in a four-wheel drive state where the torque ΔT transmitted to the rear wheels is high, so there is a limit due to the relationship between driving force and cornering force. Turning performance (limit speed during cornering) increases.

As explained above, in the torque transmission device A of the embodiment, the following effects can be obtained.

■ Since the driving piston 50 is arranged to contact the cam surface 31 from the inside in the radial direction, the centrifugal force Fc that acts on the driving piston 50 when the rotor 40 rotates at high speed creates a rotational speed difference ΔN between the front and rear wheels. Even when this does not occur, a predetermined transmission torque ΔTco is generated at high vehicle speeds, improving high-speed driving stability, and when a rotational speed difference ΔN occurs, the torque transmission characteristic with the transmission torque ΔTc added, that is, the rotational speed difference ΔN. A torque transmission characteristic (FIG. 5) corresponding to the vehicle speed V can be obtained.

Among the rotating members that rotate relatively, the oil chamber 60 and the oil passage 61 are formed in the rotor 40, which is disposed inside.
There is almost no centrifugal force effect on the hydraulic oil flowing through the rotor 40, stable torque transmission characteristics are obtained, and the oil passage 61 is compactly formed on the rotating shaft of the rotor 40 without causing whirling. be done.

■ Structurally, it is a shock absorber with 60 oil chambers.
Since the seal ring 51 alone ensures high sealing performance to prevent oil leakage, the rotational speed difference Δ is low.
Even in the N range, the transmission torque ΔT can be generated according to the torque transmission characteristics.

■ Since the cam surface 31 is formed on the inner periphery of the drive housing 30, the overall diameter of the cam surface 31 can be made large, which allows the cam surface 31 to be machined with high precision and to reduce the unevenness of the cam surface 31. Since the rotation speed becomes smooth, even if the rotational speed difference ΔN is large, collision noise between the cam surface 31 and the driving piston 5° can be prevented from occurring.

■ Since the end of the oil passage 61 is led to the accumulator chamber 64, it not only absorbs fluctuations in the oil amount, but also acts as a damper for the impact torque generated in the torque transmission system, and also acts as a damper for the sliding parts of the driving piston 50 and other parts. It also acts as a correction means for wear due to durability.

(Φ Since the opposing oil chambers 60, 60 having the same phase are communicated with each other through the communication passage 63, the mutual pressure balance, that is, the torque reaction force/9 lance is maintained, and the durability is improved.

(2) With the communication through the communication path 63, the volume (oil amount) of two cylinders is squeezed into one orifice 62, so the orifice area can be set to double. In other words, the orifice diameter is r2 times larger than the orifice of one l cylinder, and the contamination (internal dust) is
g decreases drastically. ■ Compared to the case where one orifice and reverse valve are provided for each cylinder, the number of parts is halved, the cost is low, and the reliability is improved.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention may be modified without departing from the gist of the present invention. included.

For example, the torque transmission device of the present invention is not limited to the application examples shown in the embodiments, and may be installed in the middle of the front propeller shaft of a rear-wheel drive-based four-wheel drive vehicle, or It can be provided in place of the differential of the drive vehicle, or it can be provided separately from the differential device as a differential limiting device for the left and right wheels or the front and rear wheels.

Further, although this embodiment has shown an example in which one orifice and one check valve are provided in a group of communicating cylinders, the present invention is not limited to this, and for example, as shown in FIG. As shown in the model, only an oil passage d having an orifice C may be used to communicate between communication passages a and b that communicate cylinder groups that are in phase with each other.

Further, the shape of the cam surface and the cam body, and the oil passage configuration are not limited to those in the embodiment.

Further, the transmission torque capacity can be appropriately set by changing the orifice, changing the pressure receiving area of the cam body, changing the number of cam bodies, changing the stroke width depending on the cam surface, etc.

(Effects of the Invention) As explained above, in the torque transmission device of the present invention, the flow rate generating means is integrally formed with one of the input/output shafts and has a cam surface on the inner circumference. a second rotating member that is integrally formed with the other input/output shaft and inserted into the cam surface, and a second rotating member that is supported by the second rotating member and in circumferential contact with the cam surface, and that A cam body that reciprocates in the radial direction during rotation, a plurality of fluid chambers whose volume changes as the cam body reciprocates, and a fluid path formed in the second rotating member and connecting each fluid chamber through an orifice. and a communication path that communicates a plurality of fluid chambers in the same phase with each other during the reciprocating stroke of the cam body, so that the following effects can be obtained.

■ The rotational speed increases depending on the difference in rotational speed during relative rotation between the first rotating member and the second rotating member, and the higher the vehicle speed, the more
A four-key torque transmission property is obtained in which the transmission torque generated by centrifugal force is added.

(Bo) Of the two rotating members that rotate relative to each other, the fluid chamber and fluid path are formed in the second rotating member located inside, so there is almost no centrifugal force effect on the fluid when the second rotating member rotates at high speed. In addition, stable torque transmission characteristics can be obtained, whirling does not occur, and the fluid passage is compactly formed in the rotating shaft portion of the second rotating member.

■ The structure is a shock absorber type, and the sealing performance of the fluid chamber is easily ensured, so no transmission torque is generated or a decrease in transmission torque due to fluid leakage is suppressed.

(2) Since the cam surface is formed on the inner surface of the first rotating member, the cam diameter can be made large, which allows the cam surface to be machined with high precision.

Since the unevenness of the cam surface is smoothed, collision noise caused by the cam body can be prevented even when the difference in relative rotational speed is large.

(Since it is equipped with a communication path that connects multiple fluid chambers in the same phase during the reciprocating stroke of the cam body, it is possible to maintain mutual pressure balance, and the influence of contamination is reduced by expanding the orifice area. In addition, the reduced number of parts reduces costs and improves reliability.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view showing a torque transmission bag according to an embodiment of the present invention, Fig. 2 is a sectional view taken along line I-I in Fig. 1, and Fig. 3 is a sectional view showing another example of the accumulator chamber portion. Fig. 4 is a schematic diagram showing an engine drive system to which the embodiment device is applied, Fig. 5 is a torque transmission characteristic diagram of the embodiment device, and Fig. 6 is a perspective view showing another example of the rotor part of the torque transmission device. be. 30... Drive housing (first rotating member) 31... Cam surface 40... Rotor (second rotating member) 50... Driving piston (cam body) 60...
Oil chamber (fluid chamber) 61... Oil path (fluid path) 62... Orifice 63... Communication path

Claims (1)

[Scope of Claims] 1) A flow rate generating means is provided between input and output shafts that are relatively rotatable, and flows an amount of fluid corresponding to the rotational speed difference between the two shafts, and the flow resistance of the fluid causes the flow resistance of the fluid to flow. In a torque transmission device in which transmission torque between output shafts is controlled, the flow rate generation means includes a first rotating member that is integrally formed with one of the input and output shafts and has a cam surface on the inner circumference; a second cam integrally formed with the other cam and inserted into the cam surface;
a rotating member; a cam body supported by the second rotating member and in circumferential contact with the cam surface and reciprocating in the radial direction when the two rotating members rotate relative to each other; and a volume changing as the cam body reciprocates; a plurality of fluid chambers, a fluid path formed in the second rotating member and connecting the respective fluid chambers via an orifice, and a communication path that communicates the plurality of fluid chambers in the same phase with each other during a reciprocating stroke of the cam body. A torque transmission device characterized by being a means comprising: