Archive of course projects on TMM

Contents

Description of mechanism operation. Page 2 -

Initial data....... page 4-

1. Planetary reduction gear box design..... page 7-

2. Design of involute gear engagement.. p. 10-

3. Dynamic examination of the mechanism at steady state

movement mode... p.18-

4. Design of cam mechanism. Page 29 -

Literature. p

Machine engagement

The tooth profile of the wheel to be manufactured is reproduced as an envelope of a number of positions of the initial contour of the rack tool in machine engagement. The machine engagement scheme is constructed as follows.

1. Dividing and main circles, circle of peaks and depressions are carried out.

2. From the dividing circle (taking into account the sign), the calculated displacement is deposited and the dividing line of the initial producing contour of the rack tool is carried out. At a distance up and down from the dividing line, straight boundary points are drawn, and at a distance - straight peaks and depressions; The machine-start line Q-Q is tangent to the pitch circle at point P0 (machine-engagement pole ).

3. The machine engagement line NP0 is passed through the machine engagement pole P0 tangentially to the main circle at the point N. This line forms angles equal to the straight lines of the initial producing contour of the tool.

4. The initial producing contour of the rack tool is constructed so that the axis of symmetry of the depression coincides with the vertical .

5. The tooth profile of the designed wheel is constructed, touching the profile of the initial producing circuit at point K.

To construct a series of consecutive positions of the tooth profile of the initial producing contour, an auxiliary line M-M is carried out relative to the circle of vertices, a point W is fixed - the point of intersection of the line M-M and the rectilinear part of the tool profile and the center of the circle of the rounded section of the profile - point L. Several segments of equal length are deposited on the line M-M (15-20 mm) and points I, II, III, IV, etc. are marked. The same segments are deposited on the machine-start line Q-Q (points 1, 2, 3,...) and on the arc of the division circle (points 1, "2," 3, "...). From the center O of the wheel through points 1, "2," 3,... "on the division circle, rays 01," 02, "03..." are drawn to intersect with the circle of vertices at points 1, "2," 3,... "

When rolling without sliding the machine-tool straight line along the division circle of points 1, 2, 3,... and points 1, "2," 3, "... coincide sequentially; also for points I, II, III,... and points 1, "2," 3, "...

Any intermediate position of the point W or L is the construction of the corresponding triangles.

A circle is drawn from point L2 with a radius, and a line is drawn through point WII tangentially to this circle, which gives a new position (second) of the original producing loop. All subsequent provisions (WIII, WIV, WV, etc.) are constructed similarly. To the obtained row of positions of the tooth profile of the initial contour of the tool, an envelope is carried out, which determines the left profile of the tooth of the manufactured wheel.

To construct the right tooth profile along the pitch circle of the wheel, the thickness of the tooth along the chord is deposited, where the angular thickness of the tooth along the pitch circle.

Creates a cam profile.

To construct the cam profile, we use the motion reversal method: all links of the mechanism are conditionally informed by an angular velocity equal to -k. Note here that said cam remains stationary while other links rotate at angular velocity equal in magnitude but opposite in direction of cam angular velocity.

We accept the scale of the construction. We build a circle with a radius of m (then its drawing value will take a value of mm), which is equal to the distance from the point K, to the point of intersection of the rays O.

Split the cam working profile angle (127 °) into 12 parts. We fix the points of intersection of beams from point O and circle with radius R0. Along the rays from the points of intersection, we lay segments corresponding to the movements of the pusher on an appropriate scale. By connecting the resulting points of the smooth curve, we obtain a theoretical cam profile.

To obtain the working profile of the cam, we build an equidistant profile that is spaced from the theoretical one by the value of the radius of the roller. To do this, circular arcs are drawn from the ends of the deposited movement segments with the radius of the roller. Radius of roller is selected from a number of standard sizes and by ratio. Assign the radius of the roller m (its drawing value based on the scale will take the value of mm).

The working profile is obtained as an envelope to the drawn arcs of circles .