CN101555935B - Variation-ratio non-circular planetary gear limited slip differential (LSD) - Google Patents

Abstract

The invention discloses a variation-ratio non-circular planetary gear limited slip differential (LSD) which consists of a planet gear, a central gear and a ring gear. The pitch curve of the planet gear meets the formula, wherein r1 is a pitch curve radius of the planet gear, a is a gearing central distance of the central gear, the ring gear and the plant gear, Phi1 is a rotation angle of the planet gear, n1, n2 and n3 are the changing period number of the pitch curves of the three gears, n1 can be 1, 2 and 3, n2 can be 1, 2, 3, 4 and 5, and n3 can be 3, 4, 5, 6 and 7; the pitch curve of the central gear meets the following relational expression: r2=a-r1; and the pitch curve of the ring gear meets the following relational expression: r3=a+r1. In the LSD, when two gears move relatively, the transmission ratio of a front output shaft and a rear output shaft changes according to a certain regular cycle without keeping a constant value, correspondingly, torque output ratio of two shafts changes, i.e., the torque distribution of the output shaft is automatically adjusted according to variation-ratio effect in the transmission process without changing the overall structure of a transfer case, thereby achieving the purpose of improving cross-country vehicle trafficability.

Description

Variation-ratio non-circular planetary gear limited slip differential

Technical field

The present invention relates to the system of vehicle transmission field, be specifically related to a kind of automobile shaft space difference speed device of forming planet row with noncircular gear.

Background technique

Offroad vehicle travels through be everlasting bad road or cross-country locality, for improving passing ability, generally adopts multiaxis to drive.Be rigid joint if be unkitted interaxial differential between the antero posterior axis, then when automobile running, front and back wheel will be with same angular velocity rotation.Because tire pressure, load are not the same, when particularly travelling on uneven road surface, the stroke that front and back wheel was passed through in the unit time is unequal, thereby causes trackslipping or slippage of wheel, causes power cycle but in actual use.

Differential mechanism is installed between live axle can be avoided above-mentioned phenomenon.But common cylindrical planetary gear differential mechanism will reduce the passing ability of wheel significantly, its reason is that the transfer case output torque distributes to each output shaft than ground surely by the differential mechanism velocity ratio, when wheel-slip wherein, this adhesion of wheels reduces, driving force reduces thereupon, other driving force also reduces thereupon in proportion, causes trafficability to reduce.

Summary of the invention

The objective of the invention is to deficiency, provide a kind of differential mechanism can limit the variation-ratio non-circular planetary gear limited slip differential sliding, that the vehicle passing capacity is high at prior art.

Variation-ratio non-circular planetary gear limited slip differential of the present invention, it is made up of planet wheel, central gear, ring gear, and the pitch curve of described planet wheel satisfies:

In the formula, r ₁Be planetary pitch curve radius, a is central gear, ring gear and planetary meshed center distance,

Be the corner of planetary pinion with respect to self axis, n ₁, n ₂, n ₃Be three gear pitch curve period of change numbers, n ₁Take from integer 1,2,3, n ₂Take from integer 1,2,3,4,5, n ₃Take from integer 3,4,5,6,7; The pitch curve of described central gear satisfies: r ₂=a-r ₁, the pitch curve of described ring gear satisfies: r ₃=a+r ₁

The invention has the advantages that: variation-ratio non-circular planetary gear limited slip differential of the present invention, be that three gears will forming the common cylinder satellite differential make noncircular gear into, become the non-circular planetary gear differential mechanism, when having relative movement between gear, the velocity ratio of former and later two output shafts no longer keeps definite value, but change according to the certain rules cycle, correspondingly, the ratio of diaxon output torque also changes thereupon, promptly need not change the transfer case general structure, rely on the gear ratio effect to adjust the torque distribution of output shaft automatically in the transmission process, reach the purpose of improving the cross-country passing ability of vehicle.

Description of drawings

Fig. 1 is the transfer case of automobile schematic representation;

Fig. 2 deposits star compensating gear schematic representation for existing cylinder;

Fig. 3 is the structural representation of variation-ratio non-circular planetary gear limited slip differential of the present invention;

Fig. 4 is the velocity ratio relation curve of differential mechanism shown in Figure 3.

Embodiment

Describe the present invention below in conjunction with accompanying drawing and true body embodiment.

Fig. 1 is the transfer case of automobile schematic representation, and wherein planet wheel 1, central gear 2, gear ring 3 are formed differential mechanism, Figure 2 shows that the common cylinder satellite differential, Figure 3 shows that variation-ratio non-circular planetary gear limited slip differential involved in the present invention.

In cylindrical planetary gear differential mechanism shown in Figure 2, the transformation mechanism velocity ratio:

$i_{23}^H=\frac{r_{12}\&CenterDot;r_3}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="H2009100689865E00011.png,H2009100689865E00021.png"\; state="\{\{state\}\}">r</figure-callout>}}_2\&CenterDot;{\mathrm{<figure-callout\; id="13"\; label="r"\; filenames="H2009100689865E00021.png,H2009100689865E00031.png"\; state="\{\{state\}\}">r</figure-callout>}}_{13}}=\frac{r_3}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="H2009100689865E00011.png,H2009100689865E00021.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}=c$

In the formula, c is a constant, equals the gear ratio of ring gear and central gear.R in the formula ₂-central gear Pitch radius, r ₁₂, r ₁₃-planet wheel Pitch radius, r ₃-ring gear Pitch radius.

Of the present invention variation-ratio non-circular planetary gear limited slip differential as shown in Figure 3, it is made up of planet wheel 1, central gear 2, ring gear 3, and the pitch curve of described planet wheel 1 satisfies:

In the formula, r ₁Be the pitch curve radius of planetary pinion 1, a is the meshed center distance of central gear 2, ring gear 3 and planetary pinion 1,

Be the corner of planetary pinion 1, n ₁, n ₂, n ₃Be three gear pitch curve period of change numbers, n ₁Desirable 1,2,3, n ₂Desirable 1,2,3,4,5, n ₃Get 3,4,5,6,7; The pitch curve of described central gear 2 satisfies: r ₂=a-r ₁, the pitch curve of described ring gear 3 satisfies: r ₃=a+r ₁

In of the present invention variation-ratio non-circular planetary gear limited slip differential shown in Figure 3, because each gear pitch curve no longer is round, its transformation mechanism velocity ratio:

No longer be definite value, and become the planet wheel corner

The periodic function of (around axis own).R in the following formula ₂-central gear pitch curve radius, r ₁₂-planet wheel and central gear engagement pitch curve radius, r ₁₃-planet wheel and ring gear engagement pitch curve radius, r ₃-ring gear pitch curve radius.

This effect can make full use of the adhesion on wheel and ground, improves the passing ability of vehicle.

Of particular note, variation-ratio non-circular planetary gear limited slip differential has adaptivity in function aspects, after promptly assembling, no longer need manual intervention, distribute but regulate output torque automatically according to wheel-slip situation on the different axletrees, the ratio maximum value of its output torque is called locking coefficient.

The invention will be further described below in conjunction with accompanying drawing 4 and embodiment.

This patent velocity ratio relation curve as shown in Figure 4, among the figure, dotted line is represented common cylinder satellite differential transformation mechanism velocity ratio, solid line is represented variation-ratio non-circular planetary gear limited slip differential transformation mechanism velocity ratio, can obtain from figure:

$\frac{\max i_{23}^H}{\min i_{23}^H}\&ap;3.2$

This value is equivalent to the locking coefficient of differential mechanism.

Claims (1)

1. variation-ratio non-circular planetary gear limited slip differential, it is made up of planetary pinion (1), central gear (2), ring gear (3), it is characterized in that: the pitch curve of described planet wheel (1) satisfies:

In the formula, r ₁Be the pitch curve radius of planetary pinion (1), a is the meshed center distance of central gear (2), ring gear (3) and planetary pinion (1),

Be the corner of planetary pinion (1) with respect to self axis, n ₁, n ₂, n ₃Be three gear pitch curve period of change numbers, n ₁Take from integer 1,2,3, n ₂Take from integer 1,2,3,4,5, n ₃Take from integer 3,4,5,6,7; The pitch curve of described central gear (2) satisfies: r ₂=a-r ₁, the pitch curve of described ring gear (3) satisfies: r ₃=a+r ₁

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