JPH09177934A - Ball transmitting type differential limiting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a secure differential limiting effect, by providing grooves extending continuously in the peripheral direction while bending alternatively in the axial direction, to the peripheral surfaces of output side rotary bodies, while dislocating the positions corresponding to the bending points each other. SOLUTION: When one side driving wheel loses the friction force with the road surface, for example, and when only one side drive shaft is made in the condition liable to rotate idly, the force to generate a rotation difference to cylinders 3 and 4 is applied only from one side cylinder, and as a result, at the other side of the cylinders 3 and 4, the balls 6 made in the driven side in the differential condition are liable to make the groove 3a or 4a at the active side, follow to their own movement. As a result the balls 6 receive a reaction from the groove 3a or 4a, and this reaction is operated as a force by a rolling friction and a sliding friction, so as to obtain a differential limiting effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential device mainly used in a driving force transmission system of an automobile, and more particularly to a ball transmission type differential limiting device having a differential limiting function.

[0002]

2. Description of the Related Art Conventionally, a differential gear used in a driving force transmission system of an automobile allows a difference in rotation between left and right driving wheels when the automobile travels in a curve or a difference in rotation between front and rear driving wheels in a four-wheel drive vehicle. However, if only one drive wheel rides on a road surface with extremely low friction coefficient such as snow or sand, that wheel will spin and lose the entire driving force, and you will not be able to escape from the place. It was easy to fall into. Further, even when the load on the inner wheel is extremely reduced by centrifugal force when traveling on a curve at high speed, the wheel spins idly, and the driving force for traveling at high speed on the curve is easily lost. . Conventionally, in order to make up for such a problem, for example, there is one provided with a differential limiting mechanism such as a clutch disc crimping type, even when one drive wheel is not grounded,
In many cases, preload is applied to the clutch disc to obtain the driving force, which causes this type of drive wheel to be restrained even during non-driving and deceleration when no driving force is input from the engine side. However, there was a problem in combination with a device such as an anti-lock brake system that requires independence in rotation of each wheel.

Recently, a rotation speed sensitive differential limiting mechanism using a viscous coupling has been widely used. The viscous coupling is a kind of viscous clutch that transmits the torque by utilizing the shear resistance of viscous fluid (silicon oil etc.), so that a smooth differential limiting effect can be obtained depending on the rotation difference. However, since this type also provides an initial resistance by viscous fluid, it results in being constrained between the drive wheels, though not to the same degree as the clutch disc crimping type described above.

Therefore, as a differential device having a mechanism for restricting each drive wheel during non-driving and braking and limiting the differential during driving, for example, it is described in Japanese Patent Laid-Open No. 4-271926. As described above, there is also known a torque-sensitive type that is a combination of worm gears. In this type, a pair of screw-shaped worms rotatable independently of each other on the same axis and a plurality of worm wheels having a rotation axis perpendicular thereto are engaged with each other, and when each worm is rotated, the worm wheel becomes It utilizes the unique characteristics of a worm gear, which rotates smoothly but conversely makes it difficult to rotate from the worm wheel side, thereby achieving differential and differential limiting effects according to conditions. It has the feature that it can be done.

[0005]

However, in a differential device with a rotation speed sensitive differential limiting mechanism represented by a viscous coupling, the torque transmissibility depends on the viscosity of the fluid, so that the temperature changes. There is a problem that the viscosity of the fluid changes and a stable differential limiting effect cannot always be obtained. Further, in this type, there is a problem that there is a time difference between the occurrence of the rotation difference and the time when the differential limitation is performed, and it is not possible to instantaneously respond to the change in the traveling operation. On the other hand, in the differential device using the worm gear, the differential limiting effect is stable because the differential limiting is mechanically performed, but on the other hand, the number of parts is large and the structure is complicated, There is a problem that extremely high accuracy is required for assembly and that the entire device becomes large compared to the allowable torque. In some cases, the worm gear bites the gear case while these differentials are moving, and metal powder or small metal pieces squeeze into the gear to make an unusual noise, which requires disassembling the device and cleaning the interior.

The present invention has been made in view of the above problems, and an object thereof is a ball having a simple structure and capable of obtaining a reliable differential limiting effect by selecting an appropriate material for each component. It is to provide a transmission type limited slip differential. Another object of the present invention is to provide a ball transmission type differential limiting device which is compact and advantageous for practical use, in addition to the above objects.

[0007]

In order to achieve the above-mentioned object, the present invention provides, in claim 1, a differential case which rotates about an axis by a driving force input from the outside, and a rotary shaft of the differential case. A pair of output side rotating bodies which are arranged so as to face each other in a radial direction alternately, a ball holder which is interposed between the peripheral surfaces of the output side rotating bodies and rotates integrally with the differential case, and a diameter of the ball holder. Each of the outputs is provided with a number of axially-extending slots extending in the axial direction and a plurality of balls movably held along the slots while projecting toward the peripheral surface of each output-side rotating body. Grooves extending continuously in the circumferential direction while being alternately bent in the axial direction are provided on the peripheral surface of the side rotating body by displacing every other corresponding position of the bending points, and each ball is rolled into these grooves. A ball transmission type differential limiting device that is movably fitted To have.

According to the ball transmission type differential limiting device of the first aspect, when the differential case forming the input side rotating body is rotated around the axis by the driving force from the outside, the ball holder is centered on the axis of the differential case. This rotational force is transmitted to the grooves of the inner cylinder and the outer cylinder, which are the output side rotating bodies, through the balls held in the long holes of the ball holder. Here, when a rotation difference occurs in each output-side rotating body, the balls guide the grooves to reciprocate in the axial direction of each output-side rotating body in the elongated holes, thereby interlocking the rotational movement of each output-side rotating body. , The differential of each output side rotating body is achieved.
At that time, if a force that causes a rotation difference to each output side rotating body is applied from only one output side rotating body, in the other output side rotating body, the ball that becomes the driven side during differential itself moves in the groove that is the driving side. Therefore, the ball receives a reaction force from the groove, which acts as a resistance to limit the differential between the output side rotating bodies.

By the way, when the ball is located at the bending point of the groove when the differential is not generated, the ball tries to roll along the groove without transmitting the driving force to each output side rotating body. Since the corresponding positions of the bending points of each groove are shifted by one at a time, when some balls are at the bending points of the groove, other balls are always located at the non-bending points of the groove, The driving force is reliably transmitted to each output side rotating body.

Further, according to a second aspect of the present invention, a differential case which rotates about an axis by a driving force input from the outside, and a pair of output side rotating bodies which are axially opposed to each other on a rotation axis of the differential case. A plurality of ball holders extending over both circumferential surfaces of each output side rotary body while being slidably held in the differential case in the axial direction, and penetrating each ball holder in the radial direction of the output side rotary body. Each of the output side rotating bodies is provided with a large number of balls that are held in a state of protruding in the holes provided in pairs, and the output side rotating bodies are bent alternately in the axial direction on the peripheral surface thereof. While providing grooves that continuously extend in the circumferential direction, staggering every other corresponding position of the bending points of each other,
A ball transmission type differential limiting device is constructed in which each ball is rotatably fitted in these grooves.

According to the ball transmission type differential limiting device of the second aspect, when the differential case forming the input side rotating body rotates around the axis by the driving force from the outside, each ball holder rotates around the axis of the differential case. This rotation force is transmitted to the groove of the output cylinder forming each output side rotating body via each ball held in the hole of each ball holder. here,
When a rotation difference occurs in each output-side rotating body, the balls guide the grooves to reciprocate in the axial direction of each output-side rotating body together with each sliding body, interlocking the rotational movement of each output-side rotating body,
The differential of each output side rotator is achieved. At that time, if a force that causes a rotation difference to each output side rotating body is applied from only one output side rotating body, in the other output side rotating body, the ball that becomes the driven side during differential itself moves in the groove that is the driving side. Therefore, the ball receives a reaction force from the groove, which acts as a resistance to limit the differential between the output side rotating bodies.

By the way, when the ball is located at the bending point of the groove when the differential is not generated, the ball tries to roll along the groove without transmitting the driving force to each output side rotating body. Since the corresponding positions of the bending points of each groove are shifted by one at a time, when some balls are at the bending points of the groove, other balls are always located at the non-bending points of the groove, The driving force is reliably transmitted to each output side rotating body.

Further, according to a third aspect of the present invention, a differential case which rotates about an axis by a driving force inputted from the outside, a pair of output side rotating bodies which are arranged on the rotating shaft of the differential case so as to face each other, and A ball holder that rotates integrally with the differential case interposed between the facing surfaces of the output side rotating body and a large number of holes axially penetrating the ball holder so that the output side rotating body can move in both directions. A plurality of concentric circular grooves that are provided with a large number of held balls and that continuously extend in the circumferential direction while alternately bending in the axial direction on the facing surface of each output side rotating body at the positions corresponding to the bending points of each other. Are provided so as to be displaced in the circumferential direction, and each ball is rotatably interposed between these grooves to form a ball transmission type differential limiting device.

According to the ball transmission type differential limiting device of the third aspect, when the differential case forming the input side rotating body is rotated around the axis by the driving force from the outside, the ball holder is centered on the axis of the differential case. This rotation force is transmitted to the groove of the output disk forming each output side rotating body via each ball held in the hole of the ball holder. Here, when a rotation difference occurs in each output side rotating body, each ball is reciprocally moved in the axial direction of each output side rotating body by the guide of the groove, and the rotational movement of each output side rotating body is interlocked with each other. Differential rotation is achieved. At that time, if a force that causes a rotation difference in each output side rotating body is applied from only one output side rotating body,
On the other hand, in the rotating body on the output side, the ball on the driven side tries to follow the movement of the groove on the driving side in its own direction during differential operation. The differential of the side rotor is limited.

By the way, when the ball is located at the bending point of the groove when the differential is not generated, the ball tries to roll along the groove without transmitting the driving force to each output side rotating body. Since the corresponding positions of the concentric circular groove bending points are displaced in the circumferential direction, when the ball of one groove is at the bending point of the groove, the ball of the other groove is always on the part not at the bending point of the groove. Being positioned, the driving force of the ball is reliably transmitted to each output side rotating body.

The inner cylinder, the outer cylinder, the output cylinder and the output disk which are the output side rotating bodies in the ball transmission type differential limiting device of the present invention are balls (J
Since it is subjected to repeated stress due to rolling (IS: SUJ2 product), it is necessary to select a product made of a metal material that has excellent fatigue strength and wear resistance. Therefore, in claim 4 to claim 8, in the ball transmission type differential limiting device according to any one of claims 1 to 3, the austemper having the highest strength among the spheroidal graphite cast irons. Select spheroidal graphite cast iron. This cast iron is 820 ° C-950 ° C
After austenitizing the base by holding it for 0.5 to 1 hour, it is immersed in a salt bath or the like to be rapidly cooled to 25
A constant temperature transformation treatment of 0 ° C to 450 ° C is performed, and the base is bainitized to have a tensile strength of 900 to 1200 N / mm ² ,
Austempered spheroidal graphite cast iron with elongation of 2 to 10%. The surface may be subjected to shot peening in order to improve fatigue strength.

Further, spheroidal graphite cast iron having a low carbon content martensite base is selected. After this cast iron is heated to the austenitizing temperature, it is kept at a temperature below the austenitizing temperature and above the pearlitizing temperature for a predetermined time, then quenched, and further tempered in the temperature range of 300 ° C to 600 ° C. Can be obtained by By this heat treatment, the carbon in martensite becomes low carbon, and a quenched and tempered spheroidal graphite cast iron having excellent elongation properties than those of high carbon martensite is obtained. Moreover, the thing made from alloy steel can be applied. Further, the precision castings referred to in the present invention include castings manufactured by the lost wax method,
Various alloy steels such as C material, Cr-Mo steel and SCM steel can be applied. It should be noted that the precision castings referred to here have little economic merit, but include, for example, precision castings of spheroidal graphite cast iron. However, precision castings of spheroidal graphite cast iron require heat resistance to impart wear resistance. The sintered material is a sintered material using steel powder such as carbon steel or stainless steel.

The differential case is the spheroidal graphite cast iron according to any one of claims 1 to 3, which is based on spheroidal graphite cast iron having a ferrite base, and further claims 9 to 11.
Then, in the ball transmission type limited slip differential device according to any one of claims 1 to 3, paragraph number “0016”.
Proposed are the austempered spheroidal graphite cast iron described in 1. and the spheroidal graphite cast iron having a low carbon martensite matrix described in paragraph “0017” and various alloy steels.

A ball holder according to claim 12.
According to claim 16, in the ball transmission type differential limiting device according to any one of claims 1 to 3, the austempered spheroidal graphite cast iron described in paragraph “0016”,
And spheroidal graphite cast iron having a low carbon martensite matrix, various alloy steels, precision castings, and sintered materials made of steel powder are proposed.

Further, the thrust washer must be made of a material that does not bite the inner surface of the differential case. Therefore, in claim 17 to claim 21, in the ball transmission type differential limiting device according to any one of claims 1 to 3, the thrust washer has the austemper spherical graphite described in paragraph “0016”. It proposes the application of cast iron and spheroidal graphite cast iron having a low carbon martensite matrix as described in paragraph “0017”, sintered materials, alloyed steels and precision castings. The sintered material is a sintered material using steel powder such as carbon steel or stainless steel. As the alloy steel, the same material as the washer used for the bearing and the like can be applied. Further, precision cast alloy steel or the like can be applied. The inner cylinder and outer cylinder, which are the output side rotating bodies,
Regarding the material of the output cylinder and the output disk, the material of the differential case, the material of the ball holder, and the material of the thrust washer, those proposed in the present invention can be arbitrarily selected and applied.

[0021]

According to the ball transmission type differential limiting device of the present invention, when the differential case rotates, the ball holder rotates about the axis of the differential case, and this rotational force is retained in the hole of the ball holder. It is transmitted to the groove of each output side rotating body via each ball. Here, when a rotation difference occurs in each output-side rotating body, the balls are reciprocated in the hole in the axial direction of each output-side rotating body by the guide of each groove to interlock the rotational movement of each output-side rotating body. , The differential of each output side rotating body is achieved. At this time, if a force that causes a rotation difference to each output side rotating body is applied from only one of the output side rotating bodies, the ball on the other side, which is the driven side at the time of differential, follows the movement of itself in the groove on the driving side. As a result, the ball receives a reaction force from the groove, which acts as a resistance and limits the differential between the output side rotating bodies.

1 to 6 show a first embodiment of the present invention.
FIG. 1 is a side sectional view of the ball transmission type differential limiting device, FIG. 2 is a sectional view taken along the line AA in FIG. 1, and FIG. 3 is an exploded view of the ball transmission type limiting device. It is a perspective view.

This ball transmission type differential limiting device includes a differential case 1 forming an input side rotating body, a differential case cover 2 closing one end of the differential case 1, and a pair of output side rotating bodies arranged coaxially with the differential case 1. Eggplant inner cylinder 3
And an outer cylinder 4, a ball holder 5 arranged between the cylinders 3 and 4, and a large number of balls 6 held by the ball holder 5. A thrust washer 3c is interposed between the differential case 1 and the end surface of the inner cylinder 3.

The differential case 1 has a cylindrical shape with one end opened, and a bearing 1a for supporting the inner cylinder 3 is provided in the center thereof. A flange 1b is provided around the differential case 1, and a large number of holes 1c for inserting bolts are provided in the flange 1b.

The differential case cover 2 is formed in a disc shape,
A bearing 2a for supporting the outer cylinder 4 is provided in the center thereof.
Is provided. A flange 2b is provided around the differential case cover 2, and a large number of holes 2c for inserting bolts are provided in the flange 2b. That is, the differential case cover 2 is assembled to the differential case 1 by the fastening bolts 7 that fasten the flanges 1b and 2b.

The inner cylinder 3 is formed in a cylindrical shape, and on its outer peripheral surface, grooves 3a extending alternately by bending in the axial direction are provided continuously in the circumferential direction. The groove 3a is linearly formed between the respective bending points, and as shown in FIG. 4, every other bending point is formed with a long distance and a short distance. A connecting portion 3b for connecting to the drive shaft 8 on the wheel side is provided at one end of the inner cylinder 3, and the connecting portion 3b is inserted into the bearing 1a of the differential case 1. Further, a thrust washer 3c is interposed between the differential case 1 and the end surface of the inner cylinder 3. The angles 0 ° to 360 ° in FIG. 4 indicate positions in the circumferential direction.

The outer cylinder 4 is the inner cylinder 3
It is formed in a tubular shape having a diameter larger than that of the inner cylinder 3, and the tubular portion of the inner cylinder 3 is inserted inside the tubular portion so that the circumferential surfaces thereof face each other with a space therebetween. Further, on the inner peripheral surface of the outer cylinder 4, grooves 4a extending alternately by bending in the axial direction are continuously provided in the circumferential direction. Similar to the groove 3a of the inner cylinder 3, the grooves 4a are formed linearly between the bending points, and as shown in FIG. 4, every other bending point is formed with a long distance and a short distance. When the grooves 3a and 4a are overlapped with each other, the bending points of the grooves are displaced from each other. Further, a connecting portion 4b with the drive shaft 8 on the wheel side is provided at one end of the outer cylinder 4, and the connecting portion 4b is provided.
Is inserted in the bearing 2a of the differential case cover 2.
Further, a thrust washer 4c is interposed between the differential case cover 2 and the end surface of the outer cylinder 4.
A part of the outer cylinder 4 on the other end side is divided in the axial direction, and the divided portion 4d is connected to the outer cylinder 4 via a large number of pins 4e. This structure is for facilitating the machining of the groove 4a on the peripheral surface and for fitting the ball 6 into the groove 4a during assembly.

The ball holder 5 is formed in a tubular shape and is interposed between the inner cylinder 3 and the outer cylinder 4. A large number of elongated holes 5a extending in the axial direction are provided on the peripheral surface of the ball holder 5. Further, a flange 5b is provided at one end of the ball holder 5, and the ball holder 5 is fixed in the differential case 1 by a large number of pins 5c that fit into grooves provided on the peripheral surface of the flange 5b. In this case, the differential case 1 is also provided with a groove that fits into each pin 5c.

Each ball 6 has an elongated hole 5a in the ball holder 5.
It is movably held inside along the long hole 5a, and a part of it is projected to the circumferential surface side of each cylinder 3, 4 so that each groove 3a, 4a.
It is fitted so that it can roll freely.

In the ball transmission type differential limiting device constructed as described above, the ring gear (not shown) for transmitting the driving force from the engine to the flange 1b of the differential case 1.
Is attached, and the entire apparatus rotates around the axis of the differential case 1.

Here, the operation of the ball transmission type differential limiting device is performed in the case where there is no rotation difference between the drive shafts 8 and the case where there is a rotation difference between the drive shafts 8. A case will be described in which only one falls into a state in which it easily spins.

First, when there is no rotation difference between the drive shafts 8 such as when the vehicle is traveling straight on a road surface having sufficient frictional force, when the diff case 1 is rotated by the driving force from the outside, the diff case 1 and the diff case 1 are rotated. Ball holder 5 in one
Rotates, and this rotational force is transmitted to the cylinders 3 and 4 through the balls 6 fitted into the grooves 3a and 4a of the inner cylinder 3 and the outer cylinder 4, respectively. In this case, since there is no difference in rotation between the cylinders 3 and 4, the balls 6 do not move in the elongated holes 5a and roll due to the guide of the grooves 3a and 4a, and the inner cylinder 3 and the outer cylinder 4 do not move. Rotates integrally with the differential case 1.

Next, when the vehicle is turning on a road surface having a sufficient frictional force, and when a difference in rotation occurs between the drive shafts 8 while the torque is evenly transmitted to the drive wheels, the inner cylinder 3 and Since the outer cylinders 4 rotate in opposite directions, the grooves 3a, 4a of each cylinder 3, 4
Rolls each ball 6, and each ball 6 moves into the ball holder 5
It reciprocates along the long hole 5a. That is, as shown in FIG. 4, when the respective grooves 3a, 4a move in opposite directions due to the rotation of the respective cylinders 3, 4, the balls 6 will be moved by the respective grooves 3a, 4a.
Every other groove 3 moves in the opposite direction due to the inclination of a.
When it reaches the bending point of a, 4a, it is inverted. By such an operation, the rotational movements of the cylinders 3 and 4 are interlocked with each other, and the differential of the cylinders 3 and 4 is achieved.

By the way, when the ball 6 is located at the bending point of each groove 3a, 4a when the differential is not generated, the ball 6 is
Does not transmit the driving force to the cylinders 3 and 4 and the grooves 3a and 4a
If the grooves 3a and 4a are formed so that all the bending points are coincident with each other at the same time in order to roll along
Even if the ball holder 5 rotates when each ball 6 is located at the bending point of each groove 3a, 4a, each ball 6 still has each groove 3a, 4a.
It is structurally possible that the rolling force of the ball holder 5 is not transmitted to the cylinders 3 and 4 only by rolling along the cylinders. Therefore, in the first example of the present embodiment, since the corresponding positions of the bending points of the grooves 3a, 4a are displaced by one by one, when half of the balls 6 are at the bending points of the grooves 3a, 4a. Is always located at a portion where the remaining half of the balls 6 are not the bending points, and the driving force of the balls 6 is ensured in each cylinder 3,
4 is transmitted.

Further, when only one drive shaft 8 falls into a state where it is easy to idle, such as when one driving wheel loses frictional force with the road surface, a rotational difference is generated between the cylinders 3 and 4. Since the force is applied only from one of the cylinders 3 and 4, in the other of the cylinders 3 and 4, each ball 6 on the driven side at the time of differential makes the groove 3a or the groove 4a on the driving side follow the movement of itself. And Therefore, each ball 6
Receives a reaction force from the groove 3a or the groove 4a, and this serves as resistance to limit the differential.

Here, the principle of the differential limiting effect will be described in detail with reference to FIGS. First, FIG. 5 is a view of the ball 6 and the groove 3a (4a) viewed from the radial direction of the ball transmission type differential limiting device. As shown in the figure, the center of the ball 6 is the main shaft (the rotating shaft of the differential case 1). ) The rotational force A applied from one of the cylinders 3 and 4 is acting around. Here, A≈A '(1) At this time, a force C perpendicular to the contact surface with the ball 6 is generated in the groove 3a (4a), and the component force is A'parallel to the rotational force A,
It is B perpendicular to A '. Since C is perpendicular to the contact surface with the ball 6, it is located on the line segment passing through the center of the ball 6,
When the angle formed by A ′ and C is α, the size of C is expressed by C = A ′ × 1 / cos α (2).

Next, as shown in FIG. 6, the ball 6 and each groove 3
When a and 4a are viewed from the direction orthogonal to the main axis S, the vertical reaction forces actually acting on the contact surfaces between the grooves 3a and 4a and the ball 6 are D1 and D2, and their component forces are S1 and S2. And E1 and E2 which are parallel to C1 and C2 which are perpendicular to E1 and E2. Since the ball 6 rolls while obliquely contacting the grooves 3a, 4a, C1, C2 and E1, E2 act as forces due to rolling friction and sliding friction, and E1 and E2 are called thrust forces. Since D1 and D2 are perpendicular to the contact surface with the ball 6, they are located on the line segment passing through the center of the ball 6 and D1
, D2 and the angles formed by C1 and C2 are β1 and β2, the magnitudes of the surface pressures D1 and D2 are expressed by D1 = C1 × 1 / cosβ1 D2 = C2 × 1 / cosβ2 (3). The magnitudes of the thrust forces E1 and E2 are expressed by E1 = C1.times.tan .beta.1 E2 = C2.times.tan .beta.2 (4). From the equations (1), (2) and (3), the reaction forces D1 and D2 are as follows. D1 = A × 1 / cos α × 1 / cos β1 D2 = A × 1 / cos α × 1 / cos β2 (5) C1 and C2 are C1 = A × 1 / cos α C2 from the equations (1) and (2). = A × 1 / cosα (6) Further, the thrust forces E1 and E2 are calculated from the equations (1), (2) and (4) as follows: E1 = A × 1 / cosα × tanβ1 E2 = A × 1 / cosα × tan β 2 is expressed by (7).

That is, the reaction forces D1 and D2 received by the ball 6 from the respective grooves 3a and 4a are divided into C1 and C2 and E1 and E2 components, which act as forces due to rolling friction and sliding friction, resulting in differential motion. Limited effect is obtained. At that time, the contact angles α, β 1, β between the ball 6 and the respective grooves 3 a, 4 a
By setting the magnitude of 2 arbitrarily, the differential limiting effect can be obtained as needed. Also, the thrust force E
Since the thrust washers 3c and 4c are pressed in the direction of the main shaft by 1 and E2, they generate sliding friction around the main shaft, so that a differential limiting effect is obtained. In this case, by using other inclusions such as bearings instead of the thrust washers 3c and 4c, the thrust force E1
, E2, it is possible to arbitrarily set the degree of effect of the differential limiting effect. Also, the rolling friction when the ball 6 rolls in the grooves 3a and 4a, and the ball 6 in the grooves 3a and 4a.
Sliding friction caused by rolling while contacting diagonally also becomes a factor for obtaining the differential limiting effect.

At the position where the grooves 3a and 4a contact the same ball 6, as shown in FIG. 6, the groove 3a of the inner cylinder 3 contacts from the inside and the groove 4a of the outer cylinder 4 contacts from the outside. Therefore, even with the same ball 6, each groove 3
Since the distances L1 and L2 from the contact surface with a and 4a to the spindle S are different, the thrust forces E1 and E2 generated on the cylinders 3 and 4 side are also different. Therefore, in order to keep the thrust forces E1 and E2 constant, the grooves 3a,
By setting the magnitudes of the contact angles β1 and β2 with 4a (β1> β2), the differential limiting effect generated on the cylinders 3 and 4 side can be always equalized.

As described above, according to the ball transmission type differential limiting device of the first example of the present embodiment, the grooves 3a and 4a provided in the respective cylinders 3 and 4 and the rotatably fitted therein. When the rotational force is applied from one of the cylinders 3 and 4 by interlocking the rotational movements of the cylinders 3 and 4 with each other by meshing with a large number of balls 6,
Since the differential force is limited by the reaction force (friction force) received from the contact surface with, it is not necessary to add a special mechanism to obtain the differential limiting effect, and the torque sensitive type with reliable operation is used. A differential limiting effect can be obtained. Therefore,
It is possible to realize a ball transmission type differential limiting device that is extremely small in size and low in cost, which has never been seen before. Further, it is possible to obtain a differential limiting effect as necessary by setting the contact angle between each ball 6 and each groove 3a, 4a arbitrarily. Further, in the first example of the present embodiment, the corresponding positions of the bending points of the grooves 3a, 4a are provided alternately, and when half of the balls 6 are at the bending points of the grooves 3a, 4a. Since the remaining half of the balls 6 are always located at the non-bending points, the driving force of the balls 6 can be reliably transmitted to the respective reciners 3 and 4, and the structural perfection can be enhanced.

7 to 10 show a second example of the embodiment of the present invention. FIG. 7 is a side sectional view of a ball transmission type differential limiting device, and FIG. 8 is a line AA in FIG. FIG. 9 is a sectional view taken in the direction of the arrow, and FIG. 9 is an exploded perspective view of the ball transmission type differential limiting device.

This ball transmission type differential limiting device includes a differential case 10 which forms an input side rotating body, a differential case cover 11 which closes one end of the differential case 10, and a pair of output side rotating bodies which are arranged coaxially with the differential case 10. The output cylinder 12 is formed, a large number of ball holders 13 arranged around each output cylinder 12, and a large number of balls 14 held by each ball holder 13. The thrust washers 12 are provided between the differential case 10 and the differential case cover 11 and the end faces of the output cylinders 12, respectively.
c is interposed.

The differential case 10 has a cylindrical shape with one end open, and a bearing 10a for supporting one output cylinder 12 is provided in the center thereof. A flange 10b is provided around the differential case 10, and a large number of holes 10c for inserting bolts are provided in the flange 10b. A large number of grooves 10d that slidably receive the ball holders 13 are provided on the inner peripheral surface of the differential case 10.

The differential case cover 11 is formed in a disk shape, and a bearing 11a for supporting the other output cylinder 12 is provided in the center thereof. A flange 11b is provided around the differential case cover 11.
A large number of holes 11c for inserting bolts are provided in 1b. That is, the differential case cover 11 includes the flanges 10b,
The differential case 1 by the fastening bolts 7 for fastening 11b.
It is attached to 0. Further, on the inner surface side of the differential case cover 11, a large number of grooves 11d having the same cross-sectional shape, which extend one end of each groove 10d of the differential case 10, are provided.

Each of the output cylinders 12 is formed in a tubular shape, and the outer peripheral surface of each of the output cylinders 12 has a groove 1 extending by alternately bending in the axial direction.
2a are continuously provided in the circumferential direction. This groove 12a
Is formed linearly between the bending points, and as shown in FIG. 10, every other bending point is formed with a long distance and a short distance. Every other shift. Further, a connecting portion 12b with the drive shaft 8 on the wheel side is provided at one end of each output cylinder 12, and the connecting portion 12b is inserted into the bearing 10a of the differential case 10. Furthermore, the differential case 10
Thrust washers 12c are provided between the differential case cover 11 and the end faces of the output cylinders 12, respectively.

Each ball holder 13 corresponds to each output cylinder 12
It is formed in a plate shape extending in the axial direction over the peripheral surface of and is slidably received in each groove 10d of the differential case 10. Further, each ball holder 13 is provided with two holes 13 a penetrating in the radial direction of each output cylinder 12 at a distance from each other in the axial direction of each output cylinder 12.

Each ball 14 is held in each hole 13a of each ball holder 13, and a part of the ball 14 is projected to the outer peripheral surface side of each output cylinder 12 to be rotatably fitted in the groove 12a of each output cylinder 12. ing.

In the ball transmission type differential limiting device constructed as described above, the flange 10b of the differential case 10 is
A ring gear (not shown) that transmits the driving force from the engine is attached to the engine so that the entire device rotates about the axis of the differential case 10.

Here, the operation of the ball transmission type differential limiting device is performed in the case where there is no rotation difference between the drive shafts 8 and the case where there is a rotation difference between the drive shafts 8. Each case in which only one falls into a state where it is easy to spin will be described.

First, when there is no rotation difference between the drive shafts 8 such as when the vehicle is traveling straight on a road surface having sufficient frictional force, when the diff case 10 is rotated by the driving force from the outside, the diff case 10 and the diff case 10 are rotated. Each ball holder 13 rotates integrally, and this rotational force is transmitted to each output cylinder 12 via each ball 14 fitted in the groove 12a of each output cylinder 12. In this case, since there is no difference in rotation between the output cylinders 12, each ball 14 has a groove 1
The output cylinders 12 rotate integrally with the differential case 10 without rolling by the guide of 2a.

Next, when there is a rotational difference between the drive shafts 8 while the torque is evenly transmitted to the drive wheels, such as when the vehicle is turning on a road surface having a sufficient frictional force, the output cylinders 12 are rotated. Rotate in opposite directions, the grooves 12a of each output cylinder 12 roll each ball 14, and each ball 14 reciprocates in the axial direction of each output cylinder 12 together with each ball holder 13. That is, as shown in FIG. 10, when the grooves 12a move in opposite directions due to the rotation of the output cylinders 12, the balls 14 and the ball holders 13 move in alternate directions due to the inclination of the grooves 12a. When it reaches the bending point of each groove 12a, it is inverted.
By such an operation, the rotational movements of the output cylinders 12 are interlocked with each other, and the differential of the output cylinders 12 is achieved. In addition, in the second example of the present embodiment, each groove 12
The reason why a is provided so that the bending points thereof are alternately apart from each other is for the same reason as in the case of the first example of the above-described embodiment. The angles 0 ° to 360 ° in FIG. 10 indicate positions in the circumferential direction.

Next, when only one drive shaft 8 falls into a state where it is easy to idle, such as when one of the drive wheels loses the frictional force with the road surface, the force that causes a rotation difference in each output cylinder 12 is generated. Since it is added from only one output cylinder 12, in the other output cylinder 12, each ball 14 on the driven side at the time of differential tries to follow the movement of the groove 12a on the driving side. Therefore, each ball 14 is
A reaction force is received from a, which acts as resistance and limits the differential. The principle of the differential limiting effect is basically the same as that of the case of the first example of the above-mentioned embodiment, and therefore its detailed description is omitted. Further, in the case of the second example of the present embodiment, the balls 14 fitted into the grooves 12a of each output cylinder 12 have the same distance from the main shaft (the rotation shaft of the differential case 10), so It is not necessary to change the contact angle with the groove 12a for each output cylinder 12.

11 to 16 show a third example of the embodiment of the present invention. FIG. 11 is a side sectional view of a ball transmission type differential limiting device, and FIG. 12 is a line AA in FIG. 13 is an exploded perspective view of the ball transmission type differential limiting device.

This ball transmission type differential limiting device includes a differential case 20 which forms an input side rotating body, a differential case cover 21 which closes one end of the differential case 20, and a pair of output side rotating bodies which are arranged coaxially with the differential case 20. The output disc 22 is made up of balls, a ball holder 23 arranged between the output discs 22, and a large number of balls 24 held by the ball holder 23. A thrust washer 22d is provided between the differential case 20 and the differential case cover 21 and the end surface of each output disk 22.

The differential case 20 has a cylindrical shape with one end opened, and a bearing 20a for supporting one output disk 22 is provided in the center thereof. A flange 20b is provided around the differential case 20, and a large number of holes 20c for inserting bolts are provided in the flange 20b.

The differential case cover 21 is formed in a disk shape, and a bearing 21a for supporting the other output disk 22 is provided in the center thereof. A flange 21b is provided around the differential case cover 21.
A large number of holes 21c for inserting bolts are provided in 1b. That is, the differential case cover 21 includes the flanges 20b,
21b by the fastening bolts 7 for fastening the differential case 2
It is attached to 0.

Each output disk 22 is formed in a disk shape,
A total of two concentric circular grooves 22a and 22b, which are bent and extend in the axial direction, are provided continuously on the opposing surface in the circumferential direction on the inside and the outside in the radial direction, respectively. Each groove 22a,
22b are linearly formed between the respective bending points, and the positions corresponding to the respective bending points are provided so as to be displaced in the circumferential direction. Further, a connecting portion 22c with the drive shaft 8 on the wheel side is provided at one end of each output disk 22,
The connecting portion 22c is inserted into the bearing 20a of the differential case 20. Further, thrust washers 22d are interposed between the differential case 20 and the differential case cover 21 and the end faces of the output disks 22, respectively.

The ball holder 23 is formed in a disk shape and has a large number of holes 23a penetrating the output disks 22 in the axial direction. The holes 23a are provided in a total of two rows on the inside and outside of the ball holder 23 in the radial direction, and the holes 23a on the inside and the holes 23a on the outside are staggered in the circumferential direction. The ball holder 23 is fixed in the differential case 20 by a large number of pins 23b that fit into grooves provided on the peripheral surface of the ball holder 23. In this case, the differential case 20 is also provided with a groove that fits into each pin 23b.

Each ball 24 corresponds to each hole 2 of the ball holder 23.
3a is movably held in the axial direction of each output disk 22, and the same number of rollable interpositions are provided between the inner grooves 22a and the outer groove 22b of each output disk 22. In this case, a total of two balls 24 are circumferentially adjacent to each other in each of the grooves 22a and 22b.

In the ball transmission type differential limiting device constructed as described above, the flange 20b of the differential case 20 is provided.
A ring gear (not shown) for transmitting the driving force from the engine is attached to the engine so that the entire device rotates about the axis of the differential case 20.

Here, the operation of the ball transmission type differential limiting device is performed in the case where there is no rotation difference between the drive shafts 8 and the case where there is a rotation difference between the drive shafts 8. Each case in which only one falls into a state where it is easy to spin will be described.

First, when there is no rotation difference between the drive shafts 8 such as when the vehicle is traveling straight on a road surface having sufficient frictional force, when the diff case 20 is rotated by the driving force from the outside, the diff case 20 and the diff case 20 are rotated. The ball holder 23 rotates integrally, and this rotational force is transmitted to each output disk 22 via each ball 24 in contact with each groove 22a, 22b of each output disk 22. In this case, since there is no difference in rotation between the output disks 22, the balls 24 do not roll due to the guide of the grooves 22a and 22b, and the output disks 22 rotate integrally with the differential case 20.

Next, when the vehicle is turning on a road surface having a sufficient frictional force, when a difference in rotation occurs between the drive shafts 8 while the torque is evenly transmitted to the drive wheels, the output discs 22 are rotated. Rotate in opposite directions, so that each groove 22a, 22b of each output disk 22 is aligned with each ball 24
While rolling, the output disk 22 is reciprocated in the axial direction. That is, as shown in FIG. 14, each output disc 2
Rotation of 2 causes grooves 22a, 22b of each output disk 22 to rotate.
As they move in opposite directions, each ball 24 will move into each groove 2
The output discs 22 move in the axial direction due to the inclination of 2a and 22b, and are inverted when reaching the bending points of the grooves 22a and 22b. By such an operation, the rotational movements of the output disks 22 are interlocked with each other, and the differential of the output disks 22 is achieved. In addition, in the third example of the present embodiment, the groove 22
a and 22b are provided inside and outside, and the bending points of the grooves 22a and 22b are shifted in the circumferential direction so that the balls 24 contacting the grooves 22a and 22b are not located at the bending points of the grooves at the same time. This is for the same reason as in the case where the grooves are formed so that their bending points are displaced from each other in the first and second examples of the embodiment. Incidentally, FIG. 14 shows each groove 2 when one output disk 22 is rotated by an angle of 0 ° to 30 °.
2a and 22b and the state of the ball 24 are shown.

Further, when only one drive shaft 8 falls into a state in which it is easy for the drive shaft 8 to idle, such as when one of the drive wheels loses the frictional force with the road surface, the force that causes a rotation difference in each output disk 22 is generated. Since only one output disk 22 is added, in the other output disk 22, each ball 24 on the driven side at the time of differential tries to follow the movement of the grooves 22a, 22b on the driving side. Therefore, each ball 2
4 receives a reaction force from the grooves 22a and 22b, and this serves as resistance to limit the differential.

Here, the principle of the differential limiting effect will be described in detail with reference to FIGS. First, FIG. 15 shows a case where the ball 24 and the groove 22a (22b) are viewed from the radial direction of the ball transmission type differential limiting device. As shown in FIG. 15, the center of the ball 24 is the main shaft (the rotation shaft of the differential case 20). )
The rotational force A applied from one of the output disks 22 is acting around. Here, A≈A ′ (8) At this time, a force C perpendicular to the contact surface with the ball 24 is generated in the groove 22a (22b), and the component force is A ′ parallel to the rotational force A.
And B perpendicular to A '. Since C is perpendicular to the contact surface with the ball 24, it is located on the line segment passing through the center of the ball 24, and if the angle between A'and C is α, the size of C is C = A ' It is expressed by × 1 / cos α (9).

Next, as shown in FIG. 16, when the ball 24 and the groove 22a (22b) are viewed from the direction orthogonal to the main axis, the force actually acting on the contact surface between the ball 24 and the groove 22a (22b) is There is only thrust force E parallel to the main axis. Therefore, the aforementioned component force B and thrust force E are equal, and in the case of the third example of the present embodiment, the magnitude of the differential limiting effect is determined only by the contact angle α.

A roller may be used instead of the ball in the third example of the embodiment of the ball transmission type differential limiting device of the present invention. In this case, as shown in FIG. 17 which is an exploded perspective view, a roller 26 is used instead of the ball 24 and a ball holder 23 is used instead of the ball 24 shown in FIG. 13 (an exploded perspective view of the ball transmission type differential limiting device of the present invention). The roller holder 25 is used. Roller 26 and roller holder 2
Components other than 5 are the same as those in the third example of the embodiment and are designated by the same reference numerals. The roller 26 is made of bearing steel (JIS: S
(Made by UJ) may be used, and the roller holder 25 is austempered spheroidal graphite cast iron of the same material as that applied to the ball holder 25 described above, spheroidal graphite cast iron having a low carbon martensite base, alloy steel, precision cast product. And apply sinter. Similarly, the thrust washer 22d has a sintered material,
Apply alloy steel and precision castings. As a sintered material,
A sintered material using a steel powder such as carbon steel or stainless steel, and an alloy steel of the same material as a washer used for a bearing or the like can be applied.

[0068]

As described above, by selecting and applying an appropriate material for the main parts constituting the ball transmission type differential limiting device of the present invention, a torque sensitive type extremely stable differential limiting effect can be obtained. As a result, it is possible to realize a ball transmission type differential limiting device that is extremely small and has a simple structure, which has never been obtained in the past. In addition, since the differential limiting effect can be arbitrarily set according to the application, it is excellent in versatility.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a ball transmission type differential limiting device showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an exploded perspective view of the ball transmission type differential limiting device of the present invention.

FIG. 4 is a development view of each groove of an inner cylinder and an outer cylinder that form an output side rotating body.

FIG. 5 is an explanatory view of the action of a force applied from a ball to a groove.

FIG. 6 is an explanatory view of the action of a force applied from a ball to a groove.

FIG. 7 is a side sectional view of a ball transmission type limited slip differential, showing a second example of the embodiment of the present invention.

8 is a sectional view taken along the line AA of FIG.

FIG. 9 is an exploded perspective view of the ball transmission type differential limiting device of the present invention.

FIG. 10 is a development view of a groove of an output cylinder that forms an output side rotating body.

FIG. 11 is a side sectional view of a ball transmission type limited slip differential showing a third example of the embodiment of the present invention.

12 is a sectional view taken along the line AA of FIG.

FIG. 13 is an exploded perspective view of the ball transmission type differential limiting device of the present invention.

FIG. 14 is a development view of a groove of an output disk forming an output side rotating body.

FIG. 15 is an explanatory view of the action of the force applied from the ball to the groove.

FIG. 16 is an explanatory view of the action of the force applied from the ball to the groove.

FIG. 17 is an exploded perspective view of a differential limiting device in which a roller is used instead of a ball in the third example of the embodiment of the present invention.

[Explanation of symbols]

1, 10, 20, ... Diff case, 2, 11, 21, ... Diff case cover, 3 ... Inner cylinder, 4 ... Outer cylinder, 5, 13, 23 ... Ball holder, 25 ... Roller holder, 6, 14, 24 ... Ball, 26 ... rollers, 7 ... fastening bolts, 8 ... drive shaft, 12 ... output cylinder, 22 ... output disk, 1a, 2a, 10a, 11
a, 20a, 21a ... Bearing, 1b, 2b, 5b, 10
b, 11b, 20b, 21b ... Flange, 1c, 2c,
10c, 11c, 20c, 21c ... Bolt insertion hole, 3
a, 4a, 10d, 11d, 12a, 22a, 22b ...
Grooves 3b, 4b, 12b, 22c ... Connecting portions 3c, 4
c, 12c, 22d ... Thrust washer, 4d ... Dividing portion of outer cylinder, 4e, 5c, 23b ... Pin, 5a
... Penetration long hole provided in ball holder, 13a, 23a
... through holes provided in the ball holder, A ... rotational force,
A ', B ... Component force, S ... Spindle, C ... Force generated in the groove perpendicular to the contact surface with the ball, D1, D2 ... Surface pressure on the contact surface between the groove and the ball, E1, E2 ... Thrust force, C1, C2 ... Forces perpendicular to the thrust force.

Claims (21)

[Claims] 1. A differential case that rotates about an axis by a driving force input from the outside, and a pair of output side rotating bodies that are arranged on the rotating shaft of the differential case so that their circumferential surfaces are alternately opposed to each other in the radial direction. , A ball holder which is interposed between the peripheral surfaces of the respective output side rotating bodies and rotates integrally with the differential case, and a plurality of axially extending long holes formed through the ball holder in the axial direction to rotate the respective output side. Equipped with a large number of balls that are movably held along the long holes in a state of protruding toward the peripheral surface of the body, and the peripheral surface of each output side rotating body is bent in the axial direction alternately and continuously in the peripheral direction. Is a ball transmission type differential limiting device in which each of the balls is rotatably fitted in these grooves, and the corresponding positions of the respective bending points are offset from each other. Is a spheroidal graphite cast iron Transmission-type limited slip differential. 2. A differential case that rotates about an axis by a driving force input from the outside, a pair of output side rotating bodies that are axially opposed to each other on a rotating shaft of the differential case, and a differential case. A plurality of ball holders extending over both circumferential surfaces of each output side rotating body while being held slidably in the axial direction, and two ball holders penetrating each ball holder in the radial direction of the output side rotating body. The holes provided are provided with a large number of balls that are held in a state of protruding toward the peripheral surface side of each output side rotating body, and the peripheral surface of each output side rotating body is continuously bent in the circumferential direction while alternately bending in the axial direction. Is a ball transmission type differential limiting device in which each of the balls is rotatably fitted in these grooves, and the corresponding positions of the respective bending points are offset from each other. Is a spheroidal graphite cast iron Transmission-type limited slip differential. 3. A differential case that rotates around an axis by a driving force input from the outside, a pair of output side rotating bodies that are arranged on the rotating shaft of the differential case so as to face each other, and a pair of output side rotating bodies. A ball holder interposed between opposing surfaces to rotate integrally with the differential case, and a large number of balls held in a plurality of holes penetrating the ball holder in the axial direction so as to be movable in both directions of each output side rotating body. And a plurality of concentric circular grooves continuously extending in the circumferential direction while alternately bending in the axial direction on the facing surface of each output-side rotating body by shifting the corresponding positions of the respective bending points in the circumferential direction. A ball transmission type differential limiting device in which each ball is rotatably interposed between these grooves, wherein the differential case is made of spheroidal graphite cast iron. 4. The ball transmission type differential limiting device according to claim 1, wherein each of the output side rotating bodies is made of austempered spheroidal graphite cast iron. 5. The ball transmission type differential according to claim 1, wherein each of the output side rotating bodies is made of spheroidal graphite cast iron having a low carbon martensite matrix. Restriction device. 6. The ball transmission type differential limiting device according to claim 1, wherein each of the output side rotating bodies is made of alloy steel. 7. The one of claim 1 to claim 3, wherein each of the output side rotating bodies is a precision cast product.
A ball transmission type differential limiting device according to the item. 8. The ball transmission type differential limiting device according to claim 1, wherein each of the output side rotating bodies is made of a sintered material. 9. The claim 1 to claim 3, wherein the differential case is made of austempered spheroidal graphite cast iron.
The ball transmission type differential limiting device according to any one of 1. 10. The ball transmission type differential limiting device according to claim 1, wherein the differential case is made of spheroidal graphite cast iron having a low carbon martensite matrix. 11. The ball transmission type differential limiting device according to claim 1, wherein the differential case is made of alloy steel. 12. The ball transmission type differential limiting device according to claim 1, wherein the ball holder is made of austempered spheroidal graphite cast iron. 13. The ball transmission type differential limiting device according to claim 1, wherein the ball holder is made of spheroidal graphite cast iron having a low carbon martensite matrix. 14. The ball transmission type differential limiting device according to claim 1, wherein the ball holder is made of alloy steel. 15. The ball holder according to claim 1, wherein the ball holder is a precision cast product.
A ball transmission type differential limiting device according to the item. 16. The ball transmission type differential limiting device according to claim 1, wherein the ball holder is made of a sintered material. 17. The ball transmission type differential limiting device according to claim 1, wherein each thrust washer is made of austempered spheroidal graphite cast iron. 18. The ball transmission type differential limiting device according to claim 1, wherein each thrust washer is made of spheroidal graphite cast iron having a low carbon martensite matrix. 19. The ball transmission type differential limiting device according to claim 1, wherein each thrust washer is made of a sintered material. 20. The ball transmission type differential limiting device according to claim 1, wherein each thrust washer is made of alloy steel. 21. The ball transmission type differential limiting device according to claim 1, wherein each thrust washer is made of a precision cast product.